Really, I havent really run across too many aggressive people. You talking walkers, runners, and that or caged auto fuckwads?
I find most people to be a deer in head lights or oblivious. Maybe its your stature, that can have a big effect on how people perceive you and become aggressive. I'm a big fella so no one really messes with me, though I had an incident awhile ago that I let slide, though I did mess with him for a bit without a smile on my face.