Ironically enough, it explained why I was introverted... hahahahah
No, really. I was going through all kinds of mental hell because after years of isolation, a friend took it on himself to try to socialize me - his way. I mentioned it at more length in the thread
Bringing you out of your shell.
I was feeling really confused because I wasn't responding very well at all to his efforts, and his interpretations of that were giving me all kinds of hell. I started desperately researching anything I could find that might help explain to me - and hopefully to my friend - why he really needed to just leave me alone to do it at my own pace, why his approach was not having its desired effect. I was Googling key words like "social anxiety" and "personal space" and stuff like that, and eventually a chain of links led me to an MBTI test on the humanmetrics website.
I did the test and came out as INTP, then read loads of explanations and stuff about introversion and it seemed a plausible explanation of why I was feeling so upset about all this socializing.
Of course later on I realized I was barking up the wrong tree - in fact I'm a strong extravert but wasn't liking ESFP style socializing, and besides, my social skills were stunted due to an isolated life.
It has helped me to get a sort of ball-park figure as it were, as to where I'm going wrong and what areas I need to improve on and possible sources of misunderstanding between myself and others - I wasn't willing to accept that when I was doing my best with good intentions, the reason I was having problems could be that I was just an asshole or a social retard

cos I could get on with most people just fine. But I don't take it as comprehensive... it's pop psychology really, but still useful in a limited way.