I am a Driver (with Expressive tendencies). This basically means that I am a goal oriented leader who likes to talk (no surprise to any of my friends). I move fast, make quick decisions, and don't look back unless it is to remember or learn something from my past experiences. I savor the struggle more than the accomplishment, which means I am always looking for the next objective. Thank God I found someone who will put up with me...
Now, according to Robert and Dorothy Bolton, there are four general types of people: Analyticals, Drivers, Expressives, and Amiables. The classification tends to be People vs Task oriented, and then Introverted (Ask Directed) vs. Extroverted (Tell Directed). There are tests all over the web to determine which type you are. At the very least it can be an entertaining experience.
Now, at some level, most of us probably do this, but it is interesting to start classing the people around you and seeing how different approaches impact your relationship with them. I found the book very helpful in refining my approach to the individual members of my teams, and would encourage you to read it as well. The book is available below, from Amazon: