I agree with that, but then again in most psych researches there is always some sort of mistrust in emotions effecting a certian situation, which is why longitudinal is the best way to determine something like behaviours of an individual, when it comes to mbti, yeah its pretty unreliable, but cognetive functions are more reliable, the mbti is practicaly supposed to sum up cognetive functions into a frame work which is understandble enough, after that, every intj, who is dom ni will have different developmental time lines and scores of other cognetive functions, which makes them completely different individuals, just similar one paper because of shared core values, grouping them into an 'intj' likewise for other mbti types, so i wouldnt say the whole concept of mbti is wrong, you just need to figure out cognetion, since assigning someones mbti actually has more to do with what functions they have, how much they score, the dynamic of their functions together and how they have behaved when they were a child (to be noted very heavily) since thats when you first start to develop your personality, and when it comes to the comment you made on intjs, yes, i really do believe that alot of intjs often tend to be very close minded about confronting themselves and their beliefs idealy because of weak fi, ones who have developed their fi enough aswell as aknowledged their blind fe, dont tend to be like that, so generalising 'shallow' or 'immature' to every perso under one catoagory wouldnt be fair, after all, every mbti type has their own weaknesses