ignoring function VS demonstrative function in socionics (5th function vs 6th function in mbti)
this is super useful for differing entps from intps, enfjs from infjs etc. for example, extps are TE demonstrative. they won't have any problems TE scolding you (critical parent in john beebe's system) or taking initiative and telling people what to do.
for ixtps on the other hand TE is ignoring function. an intp or istp will try to lead only when absolutely have to. why you ask, prove it you say? well, the reason why ELSE because extps are also fe tertiary while ixtps are fe inferior. ixtps do not want to deal with people.
more proof you say? well, fe tertiary for extps means fi blindspot. if your fe is trolly as an extp then your fi is gonna be worse as its shadow. extp do not give a dang about your feelings or AT LEAST, extps do not give a dang about your feelings when they clash with the logic. isn't this still good enough reason for you why extps can order people around with their te (or fe) while ixtps can't or at least won't?
socionics puts ixtps and their fi in the "role" slot. role function tries. ixtps tries to be nice. if you have some ixtps friends you will see this, you don't need a complicated 89 dichotomy based system whatsoever. whenever ixtps hurt people with their logic, they do it by mistake only.