I dont know as much about socionics as i do from jungian typology, but i do agree that inferior function is the blind spot and that a person can never develop it to the point that it would be equal to dominant function. However inferior function can be developed, but usually its still more "black and white" kind of process that doesent process all the small nuances consciously so much and being processed more by the unconscious(than dom is) it is prone on projections because unconscious material(which in the case of brain is also the processing part) is undifferentiated from each other, so this makes the inferior the "gateway" to the unconscious(shadow, anima/animus, complexes etc.). Developing inferior does not mean that you suddenly use it more, developing it means to undifferentiate it from the unconscious and instead using it consciously. But that requires much from ego to put faith in inferior function(as its conflicting material to dom which is favored by ego) and find a working balance between them. But in order to gain exp irl, the ego needs to learn to humble in front of inferior; "Where wisdom reigns, there is no conflict between thinking and feeling." — C.G. Jung
As for me, since developing some Fe i got myself into customer service job(and also sell some stuff) where i deal with a lot of people face to face, and am really enjoying it and doing good at it. Especially the elderly people like me there because of good manners, smiley face, knowing what im doing, flexibility etc. Like the other day this elderly lady wanted to donate some old and quite large encyclopedia series that we cant sell(cuz wikipedia) and taking those in is against the rules, but i told her that, but since she had carried them to us from quite far away, i told her that she can leave them to me if she has no use for them, so that she doesent have to carry them back home. Well she understood the situation and was really glad that she didnt have to carry them back home and left happy even tho she couldnt make the donation that she wanted to. And this kind of stuff is what makes people come back and can be the decisive factor when the person ponders on whether or not to come shopping in our store instead of some other, especially with elderly people who put much value in good customer service and stuff like this. Its funny that there is this ISFJ co-worker also in customer service and he would had just said to the old lady that she cant leave the books here because its against the rules. Its funny because an ISFJ should have quite well developed Fe so he should theoretically be less blind to Fe stuff i mentioned doing myself, but he is so focused on rules(and other Si stuff) that it leaves a blind spot in his Fe, while i use my Fe more consciously in many situations. Im sure that he uses his Fe in some situations more than i do, but i just wanted to show that its
situational and one can learn to not be blind to inferior all the time. Also one of the major reasons why i enjoy working in my job is because all the profits go into charity, so i get to effect the world positively even beyond making customers happy, so ultimately there is even greater Fe drive that keeps me wanting to have this job. And when it comes to social rudeness/whateverbadthing, i know quite well what is rude and what is not, but i might choose to be rude if the situation calls for it, but that decision i try to do via conscious evaluation of both T and F. I might be blunt to the point of being inappropriate with people closer to me by accident, but its just that i et stuff out more freely if im with people who i know well.
What does socionics say about this sort of stuff?
Well in Socionics, the JCF INTP is the LII (Logical Intuitive Introtratim) or the INTj (j/p stands for rational/irrational in Socionics and is lowercase to distinguish from MBTI).
LII -
(Ego Block) 1) Lead Function - Ti 2) Creative Function - Ne
(Super-Ego Block) 3) Role Function - Fi 4) Vulnerable Function (aka PoLR) Se
(Super-Id Block) 5) Suggestive Function (aka Dual-Seeking) - Fe 6) Mobilizing Function (aka Hidden Agenda) - Si
(Id Block) 7) Ignoring Function - Te 8) Demonstrative Function - Ni
The Two valued blocks are the Ego and the Super-Id, the Two unvalued blocks are the Super-Ego and the Id Block. Due to Socionics's focus on intertype relations, there is less focus on developing the Super-Id functions and more focus on finding people who use those functions, specifically the LII's dual, the ESE (ESFj), so that they may be taken care of. I don't particularly believe that the development of these functions should always be left to duals or activity partners (for LII, SEI, ISFp/ISFJ MBTI), though it would be helpful, as I'm working toward melding my understanding of Socionics and JCF due to their complementary nature from originating from Jung's initial work and thus still hold fast to the idea that one can develop the inferior (Suggestive) and the tertiary (Mobilizing) by their own accord. Also, the first two blocks (Ego + Super-Ego) are conscious, the last two are unconscious processes (Super-Id + Id)
The INTj (LII) has 4 weak functions (from the Super-Ego and Super-Id blocks), the strongest of which is Fi, the Role Function, due to its inflationary nature like the Mobilizing/Hidden Agenda Function, Si, while at the same time not being seen as pathetic when inflated (like the Tertiary function) like how Gainan describes the 'Pathetic' Hidden Agenda, but being seen as a somewhat scarily powerful function. In the JCF-Socionics cross-over assessment, the Role Function Fi is equivalent to the the Demonic Personality Complex Fi in JCF, meaning that not only does this function when activated block the lead/dominant function due to being an alternate process of the Ji function, it is used like 'a warhammer' to break those who dare cross it, including the self when expressed extremely negatively. Therefore, the LII doesn't really care about moral causes until it consciously takes up one, which can be rather scarily put forward aggressively to the dismay of Ego Fi types. The Hidden Agenda, on the other hand, is often seen as stronger by the self, but is usually read by others as 'trying-to-hard' 'pathetic' or 'sad', and since this function is Si, it is usually seen as the LII trying to prove it can take care of itself, provide a comfortable environment, and being able to know one's physical/mental limitations, and since it is an unconscious function, it inflates on its own, and often makes its way to the surface unconsciously much like the Dual Seeking Suggestive Function.
The Dual Seeking/Suggestive Function for the LII is Fe, meaning that the LII really enjoys Fe due to its complementary effect on the Ji function of Ti, and seeks to reproduce Fe in the environment but seems to always fail due to a lack of development and experience in the function. The LII, then, will unconsciously try to make the environment socially acceptable, socially comfortable, and full of the exchange of feelings, but will primarily fail due to the fact that the function is primarily unconscious and that the function is rather weak, but, unlike the Hidden Agenda, is taken more seriously by others. The LII will always try to make the environment friendly and warm, but will usually do a somewhat ok job at it.
The absolute weakest function of the LII is Se, the Point (or Path) of Least Resistance (PoLR), also known as the Vulnerable Function. Criticism in this area is taken very seriously and stings, hence the Socionics jargon for attacks on the PoLR being regarded as PoLR hits or hitting the PoLR. Interestingly, like with the Role Function, criticism to the Vulnerable function is unexpected and oftentimes is questioned, "Why is that person criticizing me for
that?". Specifically, PoLR Se makes the LII downright incompetent in physical matters such as awareness of the physical environment, assessment of the power in static objects in the environment, the realistic management of resources to achieve realistic goals, and self-assertion/imposing its will on others, and is almost impossible to develop due to its almost insidious nature and how much it is loathed as a personal weakness (in JCF, it is the equivalent to the Shadow Tertiary, Beebe's Trickster Function). Anxiety is often caused from the anticipation of having to use this function in front of others, as using it almost undoubtedly draws negative attention and criticism. Se PoLR, then, to the LII, will always be the weakest spot of the function stack, and will always be hated, but luckily, thanks to Socionics's inter-type relation system, the ESE can defend the LII's Se PoLR with Se Demonstrative, which is an unconscious, somewhat unknown rather than unvalued function in the ESE, meaning that attacks on LII's Se PoLR will empower the ESE's Demonstrative function to drive back the PoLR hitter with great force, as the Demonstrative function is strong and is perceived as aggressive/powerful like the angered Role Function. In return for the aid with Se PoLR, the LII defends the ESE's PoLR of Ni with its own Demonstrative Function of Ni.*
To summarize, Fe is wanted by the LII in the environment but the LII isn't always capable of implementing it itself, attempting to unconsciously make the environment warm, cheerful, and socially comfortable. In my own opinion, however, I still believe that it is possible to reign in some conscious control of the Fe function with development, which isn't covered that much in the Socionics system due to focus on the intertype relation system, instead suggesting that the LII should stick to what it is good at, Ti-Ne, and find an ESE to help with the Super-Id block.
* Use of the Id block functions often draws a surprised response from witnesses, as they are the opposite attitude of the Lead and Creative Functions, often drawing the specific response of "I never knew (s)he could do that as well!".