I don’t think a single trait like aggressive driving really tells you much about someone’s personality. My brother-in-law is the single sweetest, least aggressive person on the planet but used to drive (he no longer is able to) pretty aggressively. I always figured that was a situation in which he could express his inner man, but it was hardly the key to his personality. One of the most fascinating, interesting and pleasant people I know does not treat, let us say, the servant class very well. Of course this means he has some anger in him but it is hardly the key to his personality. I believe most of our personalities are a mix of traits and I am continually surprised, often in a good way, by people I thought I had figured out.