There was this big black dude (6'3" and 240 or so, I was probably 6' and around 220) in high school that was always a dick to me. I'd always nod at him or say "hi", just since I'm nice, and he'd just look away or give me mean looks. One day as we were going by each other in the hallway, he "checked" me (i.e. pushed me into lockers). As soon as he did I turned around and grabbed him and threw him into the lockers on the opposing side. He didn't say anything and just walked away. He never bothered me again.

Another time a dude who I was friends with, but who would sometimes be a dick was standing in my statistics class. It was on Saint Patricks day and his big ass (6'6" and 350 or so) decided it'd be funny to slap me across the face because I wasn't wearing green. I sat there for a moment, my fists clenched staring him in the face as he laughed. I then proceeded to shove him into a bank of desks (he landed on probably 4-5 of them). They jammed into his back and shit. The funny thing is my stats teacher watched the whole thing go down and she just sat there, staring. He and another guy put the desks back where they were and we had class as if nothing happened.