I've been playing with the Myers-Briggs Type Indicator (Jung's theory of personality type) lately. It's interesting, but it's not very precise. For example, I can clearly see my father is a classic ISTJ, but I have a tough time categorizing myself. I'm either a not so analytical INTP or a not so confident INTJ. And heck, at times, I can see that S in there too (mostly in combination with the J). I wonder how much of this is hardwired inherited predisposition, how much is learned and how much can be changed in an adult. Also, I wonder if I would even want to change if I could. A good way to find out how well you truly know your friends though. I was unable to sort them all. We're all probably too introvert to know each other well enough. How sad, when you think of it.