I found the Myers-Briggs personality analysis an incredibly helpful tool in seminary, not only for understanding myself but for understanding others. Why does my wife want to get together with others when I want to stay at home? Why did I like trigonometry when my friends were asking when they were ever going to use this stuff? Why does my mom like to take spontaneous side trips while my dad wants to reach his driving goals for the day? Why can't some of my colleagues see that it doesn't matter whether they are right or wrong if they are outvoted?
Myers-Briggs gave me a framework once upon a time for processing these sorts of interpersonal dynamics. They are massively helpful in figuring out what is going on sometimes in interpersonal conflict, as well as to know your own strengths and weaknesses. The test gives you four letters--the formal version with scales attached, because you can be more or less. I currently consider myself to be an INTP.
I have since learned more about this tool as I have been involved in implementing it into our spiritual formation sequence at Wesley Seminary at IWU. One of the middle types, I've discovered, is a person's "dominant function." So my I, T, and P are right down the middle and fluctuate. The N is what most defines me.
N--This is my dominant function, and it stands for intuitive. It is why I liked trig and calculus whether it applies to anything or not. It is why I like theoretical physics but don't care much for botany or biology. It is why I have started about thirty novels (the P is why I haven't finished any of them).
S--stands for "sensing." It is the opposite of intuiting. This is the concrete person who wants to know how something relates to the "real world." Since N is my dominant function, the S is my "inferior function." In the S domain lay my greatest weaknesses because it is the opposite of my greatest strengths.
T and F stand for "thinking" and "feeling." This type has to do with whether you are a person who makes decisions primarily on the basis of what seems logical to you or on the basis of more relational dynamics. Of course just because you are a T and you think something is logical doesn't mean it is. For example, taking relational dynamics into account is quite logical, since they exist and you have to deal with them.
But herein are many a conflict. Spouse F is blowing off steam to Spouse T. Spouse T, rather than recognize that Spouse F just wants them to listen, begins to problem solve with them. Sorry, this conversation is not about solving anything, it's about me feeling better.
So the S-N and T-F types are the ones where your dominant (and inferior) personality traits will lie. Two other dynamics then complement these basics. Are you an extrovert (E) or an introvert (I)? This is not about whether you talk a lot but about where you draw your energy--from getting alone or from getting around people. An extrovert can be quiet, and an introvert can be rather talkative (before then going off to crash somewhere).
Finally, do you like to reach closure on things (J for judging) or do you like to leave things open-ended to keep exploring or taking in more things (P for perceiving). A J likes structure and organization, finishing what s/he starts. A P likes spontaneity and informality, keeping options open. The J likes to nail things down.
These are not necessarily fixed over a person's lifetime and can vary given a person's context. I for example came out as an F in seminary, but a T more recently (I like to say that I take relational elements into account because it is logical ;-) I tested as a J in seminary but more recently as a nominal P.
The fact that I could be a J at all often comes as a surprise to people, because I consider a preoccupation with policies and structures--and obsessive tidiness--a time-wasting and often counter-productive disease. But, of course, these are J issues that relate to the S domain, which is of little interest to me. What people often don't realize is that I very much insist on organization in my intuitive life as an NJ, in my ideas. I actually went back and edited out an extraneous space from this post that was bugging me.
So these personality types are very helpful for self-analysis and interpersonal relationships. On the other hand, if you are a ESTP, you will strongly disagree with the helpfulness and accuracy of this tool. ;-)
Here's a free, but therefore not as accurate, version of the test: http://www.humanmetrics.com/cgi-win/jtypes2.asp