This article will contrast types that may easily be confused with each other. Namely the five most similar relationship pairs: activator, benefit, mirror, business, kindred (with similarity decreasing in that order), as well as other select pairs.
Completed: 30/48 (= 4*8 + 16) + 1 for quasi
ACTIVATION
(4/8 completed)
EIE/SLE
EIEs are somewhat softer and more genuinely interested in people and building camaraderie. SLEs tend more to be blunt, rude, or commit social blunders, though EIEs can say things just to be provocative. SLEs prefer more to use brute force instead of persuasion or inspiration, EIEs are more melancholic and typically less active socially and in work, and may have deeply depressive and introspective states. SLEs are more of your typical businessman workaholic who focuses on making lots of money, while EIEs have much more of an intellectual bent and are more interested in ideas and discussion for the sake of it. EIEs tend to dramatize their speech more and be more effusive, expressing even emotions that might make them appear weak like sadness or anxiety, while SLEs' expression is more limited to joking around or certain emotions like anger even if they do command a lot of attention socially. SLEs are more likely to seem "hard" or unapproachable or intimidating, and can be overbearing or demanding to underlings, while EIEs tend more to be welcoming socially, malleable, and allow more for dialog and openness to the other person's perspective, and can be influenced by others who have strong views, while SLEs can be rigid and find other perspectives threatening and go on the attack in the face of disagreement. EIEs can be aggressive but tend much less to be really physical people (like being into sports or actually physical fights) and can sometimes shrink from direct confrontation. EIEs' expression is more abstract or offbeat and they may see it as a part of their identity, while SLEs are more purely focused on the appearance aspects, which often take on a sexual or "loud" character and may be less unique and according to standards within their cultural context.
LSI/IEI
LSI is more physically present and the more active of the two types and equally if not more "expressive" in the sense of actively showing what they are feeling in the current moment on their face and with their movements. This is not what expression is to an IEI, rather it's about contemplating whether their life is an authentic representation of their longings and ideals. IEIs struggle more with lethargy and inertia, LSIs are more disciplined and less open to hearing different perspectives - IEIs may be difficult to convince but often are open to hearing about different ideas and less directly combative. IEIs are softer, LSIs often seem tough.
SEE/LIE
SEEs have strong ethics so they are a lot more filtered and careful about hurting people's feelings - LIEs are clumsy about what they say and how it is received so they often unintentionally offend or alienate people and are more likely to damage their image. SEEs care much more about image in the first place and are more diplomatic especially when they may have some use for the person. LIEs are more opinionated and argumentative; SEEs are comfortable with confrontation but not so much in the sphere of views and logic.
LIEs have strong intuition so they are more careful and less reckless and also typically have more intellectual interests that aren't directly about the here and now. SEEs are more directly physical and vigorous people and tend to be more sporty. SEEs care more about personal appearance.
ILI/ESI
They are both types that tend to be critical, negative, and withdrawing from people or situations that don't suit them.
Differences are that ESIs are more proactive, more social, more involved in the world, and more physically organized. ILIs are more intellectual and in their heads, but lazier when it comes to getting stuff done (low Se). They also tend to be more purely rejecting of people instead of interacting with them as needed as ESIs do.
BENEFIT
(8/16 completed)
LII/IEI
LIIs are more plain-speaking and direct, IEIs tend to dramatize or exaggerate due to higher Fe (blocked with Ni). IEIs also sometimes have aspirations to be in some position of power and respect even if they don't act on them. LIIs care more about relatability and making concepts accessible or simpler (even if they are not always successful in doing so), IEIs can sometimes be pretentious or like to make things baroque or impressive. LIIs have more naive curiosity about things, IEIs are somewhat more jaded and can be paranoid or skeptical of people's motivations. IEIs tend to reject the importance of mundane everyday life (and improving its quality) while LIIs tend to be more deeply interested in it and see it as a source of comfort or enjoyment. IEIs are generally more dramatic and comfortable with chaotic or conflict-filled environments or controversial individuals, LIIs tend to be put off by them and avoid them. And IEIs have better people skills generally and tend to be more interested in other people. IEIs also tend to agonize over whether their career path and general life trajectory is meaningful and fulfilling, LIIs see things more in terms of boredom/interest/fun (Ne+Fe as opposed to Ni+Fe) and generally feel less locked in by decisions, that other possibilities can still happen.
ILE/EIE
ILEs are much more mild and less antagonistic than EIE, they really aren't "the trolling type" if you interpret that to mean doing caustic, edgy, controversial things to get a reaction, really that's a Beta trait. ILEs are more chill and less dramatic, can be unreasonably naive (about both people and ideas) while EIEs are often cynical and mistrustful. EIEs can enjoy conflict while ILEs typically are uncomfortable with it and avoid it. ILEs have higher Ti and generate systems of their own more than EIEs, and are more organized in their thought process and tend to be more stable in their opinions or conclusions about things.
EIE/SEE
SEEs are more independent, and typically more focused on work, being productive, and acquiring wealth, while EIEs are more impractical and idealistic and think more about society at large. SEEs are more physical and determined and can be more shallow about appearance. EIEs care more about appealing to others/"the crowd". SEEs are sometimes more judgmental, tend to bear grudges. SEEs have more of a filter and willingness to back off in conflict if it doesn't seem like the other person will be swayed. EIEs are softer and more malleable, more hesitant, more imaginative, have more foresight, more prone to exaggeration and grandiosity.
LII/SLI
SLIs' attitude is more like "if it ain't broke don't fix it" while LII is more proactive when it comes to abstract goals and especially intellectual pursuits (strong Ne + Ni). SLIs can be uncurious but are more on top of managing their physical environment. SLIs are less communicative, more dry and distant, not as open to interaction (1P Fe), they aren't driven to participate socially in a way that requires active communication although they may be present passively in social spheres, LIIs are more energized by social participation. LIIs are more physically awkward, SLIs are more graceful. LIIs are more idealistic, SLIs are more practical. SLIs tend to be more lackadaisical and less responsive when it comes to responding to external emotional pressure or demands.
SEI/EII
SEIs tend to have more fluid and overtly positive and enthusiastic expression. They are also less standoffish, and prioritize harmony over their personal judgments and feelings about people, so they tend to be perceived as more friendly. EIIs can sometimes be "prickly" and are often emotionally neutral or dry.
EIIs are also more intellectually inclined due to higher Ne and Ni, and more physically awkward.
EIIs are also more focused on work and productivity, SEIs tend to be more into artistic expression or aesthetics. EIIs are also more proactive in researching various ideas that are outside of everyday life due to higher Ne.
ESE/IEE
ESEs are more proactive, energetic, and socially extroverted (high Se). IEEs tend to be more moody and introspective (higher Ni), but sensitive and respectful of personal boundaries (high Fi). Also more intellectually inclined due to strong intuition. IEEs are more spacey and sometimes physically awkward. Softer expression than ESEs and appear more socially reserved in general. ESEs are somewhat more choleric and can momentarily express strong negative emotions even if they are predominantly positive.
LIE/IEE
LIEs are a lot more direct, less subtle/sensitive, and can be rude due to low Fi and Fe. IEEs are more comfortable talking about emotional topics and are far more interested in people psychologically, and tend to ask questions to probe them. They are also more aware of their own psychology. LIEs are more hard-nosed, IEEs tend to be overly optimistic and Pollyannaish. Since they value Ni, LIEs are sometimes extremely cynical, critical, and negative about new ideas, and are rather loud about their criticisms, they tell it like it is. IEEs are much less likely to alienate people and generally get along with most people. Both types can be somewhat awkward but IEEs are fairly relaxed while LIEs tend to be impatient and want to move forward constantly.
SLE/LIE
LIEs have more foresight and are more careful and less reckless due to higher Ni, but are less physical and less physically imposing people, and often appear nerdy.
SLEs care more about dominance (Beta Se) and tend to have more fixed views due to valued Ti and lower intuition. They tend to be more ideological and care more about group or ideological affiliation than LIEs who are more solely focused on pragmatic effects or economic issues. SLEs are more social and more like entertainers, LIEs can be jocular but don't focus on others' reactions as much. SLEs care more about personal appearance and impressive physical possessions generally.
SLEs also care more about engaging in arguments to try to convince others (Fe) or defeat their views while LIEs are less likely to put in the effort to try to change others (Fi values).
MIRROR
(8/8 completed)
ILE/LII
ILEs are more purely positive, LIIs have more negativity and skepticism due to 4D Ni. ILEs are more active and focused on getting things done in the real world, LIIs are more focused on abstract, self-contained systems and refining their organization instead of expanding their functionality (Ti > Te). LIIs are more committed and focused on fewer things (high Ni) while ILEs tend to jump around more and may abandon things when they lose interest. ILEs are much more comfortable in the spotlight due to higher Fe and care more about how to make ideas accessible and interesting to others, instead of just working on the ideas themselves. ILEs also tend to end up in public-facing leadership positions more.
SEI/ESE
ESEs are more pushy, they like to stay busy, SEIs are more restful and inoffensive. ESEs are more proactive in trying to appeal to others, more obviously enthusiastic, SEIs can be quite demure and withdrawing at times if they aren't comfortable with a social situation.
SEIs are more respectful of personal boundaries (4D Fi), ESEs can be intrusive or pushy in how they try to help people. SEIs are more comfortable with detailed work, ESEs may be disorganized or more careless with details.
EIE/IEI
EIEs have much more presence socially whereas IEIs tend to fade more into the background or be reserved. IEIs may even be perceived as unexpressive facially despite being internally dramatic or performative. IEIs are much more intellectual and analytical due to mobilizing Ti. EIEs act much more spontaneously in the moment while IEIs often feel paralyzed by fear or uncertainty or stuck in their heads.
EIEs generate different possibilities or ideas about things, almost to a fault, where they can constantly oscillate in what they think and become confused or overwhelmed by the different perspectives (4D Ne, 1D Ti). By contrast IEIs are more stubborn and slower to change what they truly think even if they may give ear to alternative perspectives.
EIEs' social interaction is fluid and they don't usually limit who they interact with if they find the other person entertaining or interesting (Fi ignoring). IEIs can display somewhat sharp personal judgments at times and hold grudges more, and tend to withdraw more socially. IEIs are more comfortable interacting one on one and can be "the therapist friend" due to higher Fi.
IEIs are more stable and can get stuck in a routine, while EIEs generally have no problem introducing novelty and stimulation to their lives, but at the expense of being more chaotic and overdoing things.
LSI/SLE
SLEs don't care about hierarchy and order so much as they care about being in a dominant position. LSIs are the ones who want things to be in order in a more impersonal way - although they still may seek positions of power they are more comfortable being at a middle level in the hierarchy, like a bureaucrat or police officer or something. SLEs are much more comfortable and even revel in uncertainty and chaos, while LSIs dislike it. SLEs are also more likely to be tolerant of crass or rowdy social behavior, LSIs are choosy about how they participate and have less of a social battery. LSIs are more attentive to their state of comfort and health and sometimes take a deep interest in health (high Si). SLEs are more chaotic and fast-moving while LSIs are slower and attentive to detail and quality of work, but also more prone to micromanage. LSIs are more moralistic or principled while SLEs are often amoral.
ILI/LIE
LIEs make their presence known a lot more, ILIs tend to be reserved and fade into the background. LIEs are often active and somewhat social people, ILIs are reclusive and not particularly enterprising. LIEs are more positive although they can also be cynical and caustic like ILIs. LIEs are more talkative and can be charismatic to a degree. ILIs are somewhat more polite in the sense of having more of a filter and not necessarily saying what is on their mind. LIEs tend to overdo things and take more risks, ILIs are more careful. LIEs are also more proactive in helping others with practical tasks, ILIs let others take the initiative. ILIs are more theoretically oriented and into arcane details, LIEs tend to be more purely focused on pragmatic or task-oriented aspects of work.
SEE/ESI
ESIs are more meticulous and detail-oriented, SEEs are more messy and disorganized. ESIs have more of an inclination to domestic things, while SEEs are more typical than ESIs as entrepreneurs or leaders. Both can be impulsive but SEEs are more impulsive and more reckless. ESIs are more likely to be nervous, anxious, and unsure of themselves, and to make concessions to others or approach conflict indirectly for the sake of relationship harmony, while SEEs tend to be more consistently self-confident/arrogant/independent. SEEs are somewhat more likely to be pushy or overstep personal boundaries, ESIs are more careful of that or likely to avoid people they don't like. ESIs tend to be more cold although they are also paradoxically more warm and display more vulnerability than SEEs - SEEs are more likely to behave in an informal/joking/cheerful way. SEEs tend to do things to excess (e.g. consumption), ESIs have more restraint and attention to the need to rest and relax.
EII/IEE
IEEs are a lot more proactive and tend to take more leadership roles. EIIs are more socially closed and pay more attention to details. IEEs are much more verbal and take on a wider variety of projects which they don't commit as much to. IEEs are more spontaneous and joke around more and are more aware of how others are receiving them, while EIIs may be withdrawn or ramble about their inner experience. EIIs are much less sure of themselves and tend to be more socially anxious.
LSE/SLI
LSEs are more active, warm, and expressive or at least enthusiastic, SLIs are more lethargic and deadpan. LSEs take more initiative with new things and have more innate curiosity, SLIs tend to stay in their comfort zone and only take action when the existing equilibrium is disturbed. SLIs are more judgmental or likely to get annoyed with others, but tend to have more foresight while LSEs generally have a naive attitude towards the possibility of future problems. LSEs are more focused on being of service to others and actively acquiring resources while SLIs tend to keep to themselves and are much less responsive to communication and demands for interaction.
BUSINESS
(4/8 completed)
EIE/LIE
LIEs tend to be more focused on work and accomplishing practical things. They are more skeptical and less concerned with ideology or ideals than EIEs, who are often quite idealistic. LIEs are less introspective and have less of a sense of what personally motivates them (other than e.g. a generic desire for productivity or financial independence), rather they tend to address whatever task is at hand. EIEs have a much wider emotional range and are more dramatic, while LIEs tend to display a narrow range of emotions (like anger or enthusiasm for example). EIEs are more concerned with social trends and social significance, LIEs don't really pay attention to that and are more focused on what is relevant to them personally.
SEI/IEI
SEIs tend to want to maintain a positive and welcoming atmosphere and get along with everyone, IEIs are more comfortable being controversial or stirring things up. SEIs tend to want to blend in and be normal, relatable people, IEIs generally emphasize their uniqueness and special qualities and can be elitist. IEIs tend to be much more intellectually inclined and also more reclusive. IEIs tend more to be into abstruse or arcane topics and use abstruse language that people might not understand, while SEIs tend to stick to everyday language that everyone can understand (which again relates to blending in vs standing out and relatability).
LSI/ESI
ESIs' judgment is primarily based on individual character and specific actions and trustworthiness (Fi), LSIs' judgment is primarily based on principles or ideology or group membership/allegiance (Ti).
ESIs are much more likely to disengage from people they dislike or who confront them, LSIs have a harder time disengaging and not reacting when it comes to confrontation. So LSIs are more outwardly aggressive. LSIs are more outspoken about their opinions and also more attracted to non-serious social atmospheres. LSIs are more intellectual generally and interested in discussing abstract ideas.
LSIs are more confrontational and reactive because of Fe valuing - LSIs tend to view people collectively and value convincing others of their opinions (Ti). ESIs have a more skeptical view on others and tend to think that they won't change (FiNi), and they will simply avoid people who are wrong or bad in some way because it suggests that they aren't compatible.
ILI/SLI
SLIs are much more nonverbal, they feel their way through things, ILIs are more intellectual and likely to go on lengthy digressions. In general SLIs (over)simplify things and ILIs (over)complicate them, due to Si and Ni values respectively. SLIs are usually physically engaged with their environments and may have interests in low-key physical activities that may involve engaging with nature (like sports, fishing, or hiking). ILIs tend to live more in their minds or in virtual spaces. SLIs are softer and more conflict avoidant and less confrontational and rigid, ILIs tend to be more harsh and cynical and can be iconoclastic. ILIs express more negative emotions (anger, angst, hatred, etc.) than SLIs, although both can be grumpy and terse. SLIs are conflict-avoidant (and avoid negative emotions expressed by others), while ILIs can be combative and are comfortable being around provocative and crude people.
KINDRED
(7/8 completed)
SEI/SLI
SEIs are warmer and more expressive and interested in other people as a rule. SLIs are more independent, they tend to do their own thing and don't seek out social groups as much. SEIs are fairly passive but they can enjoy being around groups. SEIs are more self-sacrificing and other-focused to a fault, SLIs are highly nonverbal and struggle with communicating (especially communicating intentions) and are avoidant, especially when it's about unpleasant things.
ESE/EIE
EIEs seek unbridled expression and often to expand the audience that receives their expression. They often seek to be in a position where they can be the center of attention somehow, like an orator or performer or community leader. They may use this position to convey some kind of message or simply to express their uniqueness and stand out. They can be quite combative and skeptical due to valuing Se and Ni. EIEs are far more intellectual than ESEs due to higher Ni and can be obsessed with fictional worlds or fantasy, while ESEs are much more grounded.
ESEs instead seek to create a welcoming atmosphere for everyone, and generally adopt a proactive but servile, helping role. They tend to dislike negative or controversial expression for that reason because it will create conflict and be less inclusive. They tend to want to see everyone as being on the same level and don't try to be unique or influence others in the way that EIEs do. They try to make sure people are happy in the here and now instead of trying to direct the course of things on a grander scale or reflect on the deeper meaning of things. Their expression is more anodyne and "samey" unlike EIEs who can be volatile or controversial or have wild mood swings.
ESEs are usually much more organized in their physical environment and routines than EIEs, who may struggle to maintain daily activities.
SLE/SEE
SLEs are typically much more unfiltered and more engaged in interaction in a way that crosses personal boundaries. SEEs are more likely to have strong feelings about who is or isn't worth their time, and to withdraw from open conflict if it wouldn't be productive.
SEEs are generally more personable and more scattered, but less rigid and commanding. They are more likely to evaluate things on a case-by-case basis than according to strict rules or codes like SLE.
Due to valuing Fe SLEs care a lot more about how they are coming across and SEEs, while expressive, can also be cold and standoffish, and don't particularly care how their expression is received. And SLEs are more likely to hurt people's feelings accidentally or just be blunt and offensive.
Despite some claims to the contrary, SLEs aren't really "more serious" than SEEs - SEEs are colder in the sense of not always being responsive to other's invitations to interaction and intentionally avoiding interaction when it's with someone they don't like. SLEs have less of an emotional range and less subtlety, but they tend to be somewhat louder and more in-your-face.
SLEs are also more intellectually inclined and more interested in abstract systems or e.g. political ideologies even if both types are generally disinterested in ideas that have no bearing on the real world.
LIE/LSE
LIEs tend to be much more loud, controversial, opinionated. More like workaholics who don't have much of a work/life balance compared to LSEs. LIEs are a lot harsher and more judgmental.
LSEs are not "administrators" or your typical accountant, usually they are focused more on providing useful services directly than managing other people, indeed that's probably more of an LIE thing since their visions tend to be grander and of wider scope.
LSEs tend to be more optimistic (sometimes naively so) due to 4P Ne, LIEs are quite cynical or negative at times.
ILE/IEE
IEEs are generally softer, more personable, moodier (due to having strong and valued Fi), ILEs are more unfiltered and positive due to valuing Fe (with Si), and they like to talk (or argue) about ideas and the logic behind them, they're much less discriminating about who they interact with and what information they divulge as long as the interaction and discussion is enjoyable (Fe > Fi).
ILEs are less sensitive to others' feelings, but also tend to be less judgmental. ILEs are more interested in structured thinking or systems of thought, IEEs are more focused on exploring others' experiences and ways of life on an individual or cultural basis.
IEI/ILI
IEIs tend to be romantic idealists, who create some mental picture of how things should be in their lives and feel unfulfilled if the ideal isn't realized. ILIs are imaginative but are much more hard-nosed realists when it comes to understanding what is achievable or not, in fact they tend to overdo skepticism and shoot down even ideas that could work but aren't proven yet. ILIs are much more judgmental and tend to move away from people; IEIs don't really care as much about people's individual character and can interact cordially with people they don't like to avoid spoiling a group atmosphere. ILIs tend to have some interests related to work while IEIs consider working specifically for a living to be a necessary evil. IEIs may want to be in a position of recognition and may try to appeal to others, ILIs are less likely to use positive means to appeal to people although they may try to improve their status by criticizing others.
IEIs are more into abstruse symbology or arcane systems, ILIs take a more idiosyncratic and less systematic approach to analyzing things.
ESI/EII
EIIs are less physically organized and less disciplined than ESIs. Also they tend to be much more forgiving / less judgmental than ESIs.
ESIs are more paranoid and more careful with personal information, EIIs are somewhat more open and verbal. ESIs are more socially extroverted, EIIs are more shy and can be nerdy/intellectual/bookish.
QUASI-IDENTICAL
ILE/LIE
ILEs are much more naive and positive, LIEs tend to be more abrasive, aggressive, critical, and concerned with material success, getting real results instead of engaging in idle talk. ILEs are more socially welcoming and less likely to engage in crude humor, and more likely to want to include everyone and convey or promote ideas to a general audience (though LIE can too).
CONTRARY / EXTINGUISHMENT
Normally I would not even address this one because contrary types tend to be very different, but it is worth dispelling some common misconceptions about the supposed similarity between LSI and LSE. One way to see the absurdity of this is that people rarely say that e.g. ESEs and ESIs are similar, or EIIs and EIEs. The reason is that Se valuing was not understood very well in the early days of socionics so that certain types like LSE were essentially described as valuing Se (or Si, as with LIE).
LSI/LSE
These types are not very similar, one has 4P TiNi with 1P TeNe and the other has 4P TeNe with 1P TiNi, so they have polar opposite values. LSIs value certainty and limiting information, LSEs value expanding information and possibilities. LSIs are the type to get anxious about the future and neurotically plan to mitigate anything going wrong (Ni mobilizing) while LSEs tend to be (overly) optimistic about the future and their capability to deal with any problems that might arise in the moment (Ne mobilizing).
LSEs value Si so they are generally peaceful and conflict avoidant, despite being industrious and energetic (4D Se). For LSI Se is valued so they are more confrontational generally, despite caring about the quality of their environment (4D Si).