I first encountered with MBTI in 2019 and instantly became obsessed with it. Until then I had literally no idea that people can have different functions to process their inputs. I was suffering a lot by thinking that people do process the data in similar ways but output vastly different results. I was feeling like an outsider because no one was behaving like me. How could no one behave like me if they see what I see!? MBTI was the wake up call for me to understand people are different.

Being an INTJ also helped me to build self-esteem because everyone was saying how INTJs are rare and how smart they are. Being an INTJ became my identity. Then I decided to break that identity and tried to convert myself to an INFx. I was detached, I was cold and I was blaming my Te (?) function. If I could turn it into Fe maybe I could connect with a part that I locked in when I was a child.

Then I started to not care about MBTI. Thinking now, it feels like a psuedoscience. But Jungian parts are worthy frames to see how people operate.

(I)ntroversion vs (E)xtraversion

The introvert's attitude is an abstracting one; at bottom, he is always intent on withdrawing libido from the object, as though he had to prevent the object from gaining power over him. The extravert, on the contrary, has a positive relation to the object. He affirms its importance to such an extent that his subjective attitude is constantly related to and oriented by the object. The object can never have enough value for him, and its importance must always be increased. — Carl Gustav Jung

In Jung's theory some functions are extraverted and some functions are introverted.

We must observe which function is completely under conscious control, and which functions have a haphazard and spontaneous character. The former is always more highly differentiated than the latter, which also possess infantile and primitive traits. Occasionally the superior function gives the impression of normality, while the others have something abnormal or pathological about them. — Carl Gustav Jung

I(N)tuition vs (S)ensation

Introverted Sensation: Si
Extraverted Sensation: Se

Introverted Intuitive: Ni
Extraverted Intuitive: Ne

(T)hinking vs (F)eeling

Introverted Thinking: Ti
Extraverted Thinking: Te

So in judging whether a particular thinking is extraverted or not we must first ask: by what criterion does it judge—does it come from outside, or is its origin subjective? — Carl Gustav Jung

Extraverted thinking focuses on objective data and therefore more easily recognized. It's how rationalists mainly operate: receive objective data from outside, test it against the internal model, repeat.

In its essence [extraverted] thinking is no less fruitful and creative than introverted thinking, it merely serves other ends. This difference becomes quite palpable when extraverted thinking appropriates material that is the special province of introverted thinking; when, for instance, a subjective conviction is explained analytically in terms of objective data or as being derived from objective ideas. For our scientific consciousness, however, the difference becomes even more obvious when introverted thinking attempts to bring objective data into connections not warranted by the object—in other words, to subordinate them to a subjective idea.

Introverted thinking is prone to confuse the map with the territory.

Introverted Feeling: Fi
Extraverted Feeling: Fe

(J)udgmental vs (P)erceptive

I thought Judgmental and Perceptive types were Myerrs-Briggs addition to Jung's personality types theory but Jung says: