Everybody is different, but trying to deal with and understand and work effectively with five bazillion individuals is rather a hard task. This is one reason people chunk everybody else into endless numbers of categories. One type of category I've been reading up on lately is dietary. A quick glance through my local bookstore finds a plethora of theories regarding what types of food to eat:
Personally I think none of these are completely right nor are any of them completely wrong. They all can be useful in learning how to listen to what your body is telling you will fuel it best.
Another category I've been learning about is personality types. Probably you've heard about the Myers Briggs Type Indicator that rates you along four different axes. I'm an INTJ, which supposedly only two to three percent of the world's population is. (It seems that most of us are programmers though!) My wife is partial to Enneagram; in that classification I'm a One and Five. My favorite is Human Dynamics, where I'm clearly a Mental Physical (again the rarest type) but also have a strong Emotional Objective minor. As with diets, there are a plethora of other classifications as well, and none of them are completely right nor are any of them completely wrong.
Each of them, however, can be useful in understanding other people. Here's an example: I was discussing this recently with one of my team, and she related how when she interviewed with me she thought she had completely bombed because she wasn't able to read me at all. Now that she knows I'm a Mental Physical, though, she can see that that's just how I am - I don't surface my emotions (not that I have many to start with). Knowing my type helps her translate my actions into her frame of reference, and knowing her type helps me do the same.
I wonder how many personality conflicts and angry meetings and such are simply due to misunderstandings resulting from viewing a statement or action from an invalid viewpoint. Understanding personality types - even if you don't know the specific type of the other person - will help you make up for not having a babelfish to translate other people's actions.
*** Want a fun job on a great team? I need a tester! Interested? Let's talk: Michael dot J dot Hunter at microsoft dot com. Great coding skills required.