The test is largely bullshit, but the function stack that underpins the MBTI concept is a good model of the way people think.
It just turns out that discovering somebody's function stack is way harder than it looks. Rather than take a test, it's best to study the functions, pay attention to how you think, and suss out how your function stack works.
Of course, the MBTI letters that are used to describe the types are misleading. You look at INTJ and think "somebody who favors introversion, intuition, thinking, and judging", and that's such a horrible oversimplification it's easy to dismiss. But if you're familiar with the function stack, then you know INTJ is code for "introverted intuition > extraverted thinking > introverted feeling > extraverted sensing" (for short: "Ni > Te > Fi > Se"), and if you know how those functions are defined, then you can actually get a decent grasp on how an INTJ thinks.
I can say that from doing a lot of introspection that my four functions are Si, Fe, Ti, and Ne. I have still yet to suss out the exact order of my functions, and that appears to change with my mood. The two most plausible orders for me are Si>Fe>Ti>Ne and Ti>Ne>Si>Fe, which would make me either ISFJ or INTP, respectively. The usual descriptions of both types resonate very strongly with me in different situations (but never at the same time), and I can't say the same about any other type. One thing to note is that people can develop their weaker functions to the point where it becomes possible to emulate a type with the same functions but in a different order (there are four such clusters consisting of four types each), so maybe I'm just good at wielding my lower functions.
Fascinating that you think you may be ISFJ or INTP. I am married to an ISFJ and have a few ISFJ friends and they are quite a bit different from my INTP friends and family members.
It just turns out that discovering somebody's function stack is way harder than it looks. Rather than take a test, it's best to study the functions, pay attention to how you think, and suss out how your function stack works.
Of course, the MBTI letters that are used to describe the types are misleading. You look at INTJ and think "somebody who favors introversion, intuition, thinking, and judging", and that's such a horrible oversimplification it's easy to dismiss. But if you're familiar with the function stack, then you know INTJ is code for "introverted intuition > extraverted thinking > introverted feeling > extraverted sensing" (for short: "Ni > Te > Fi > Se"), and if you know how those functions are defined, then you can actually get a decent grasp on how an INTJ thinks.
I can say that from doing a lot of introspection that my four functions are Si, Fe, Ti, and Ne. I have still yet to suss out the exact order of my functions, and that appears to change with my mood. The two most plausible orders for me are Si>Fe>Ti>Ne and Ti>Ne>Si>Fe, which would make me either ISFJ or INTP, respectively. The usual descriptions of both types resonate very strongly with me in different situations (but never at the same time), and I can't say the same about any other type. One thing to note is that people can develop their weaker functions to the point where it becomes possible to emulate a type with the same functions but in a different order (there are four such clusters consisting of four types each), so maybe I'm just good at wielding my lower functions.