Is anyone here familiar with the Enneagram? If not, you can read more about it here: www.enneagraminstitute.com
It's similar to MBTI, but it focuses more on motivations and fears, and it's simple enough that it's easy to keep track of all the personality types and identify people you know well. Ever since I was introduced to it a few months ago, I feel like I've been able to understand other people a lot better, especially regarding why and how expressions of the false self differ among people.
If you're trying to determine your own personality type, I would recommend reading through the different descriptions to see which one fits you best, because I haven't found the tests to be very accurate. I feel like it has given me a lot of insight aspects of my own personality that I often struggle with, mainly regarding why I feel so different from everyone else. (I'm type 5 wing 6).
The only doubt I have about it is that I haven't found any scientific studies proving it's applicability. I believe it is used mostly by Catholics and other religious groups, which makes me skeptical, but it does seem a lot more evidence-based than astrology and other stuff like that. Personally, I've been able to determine the personality type of almost everyone I'm close to, so it seems to correspond to reality. I'd like to know what other people here think about it and its usefulness.