I was bullied a lot in high school for a myriad of reasons, I kept to a small circle of friends, I didn't talk to girls much, and I took part in 'uncool' activities. At the time I was in competitive gymnastics, so I had a wiry strength that most people did not foresee.
I was helping clean up after a game of dodgeball when one of the new students (his and my schools merged) who had taken a liking to picking on the smaller guys, like me, decided to have an extra 'overtime' with me. He had been antagonizing me with chronic name calling, and shoving in the halls, and I was having a hard time coping (I was in a bad place then), so when he picked a fight with me in the gym I couldn't handle it, he was pretty shocked that he got such a volatile reaction out of me, so I was able to get off the first hit, the only hit, the guy toppled from a well delivered running haymaker to his nose (which is still crooked). By the time the guy could see again our gym teacher had dragged him (literally) and me (figuratively) to his office. The guy was sent home and I got a two day suspension, followed by the remainder of the week in-school (him starting the 'fight' was witnessed by a full gym class, he had it coming)
He left me alone the rest of the year, and I have since grown up a lot, that was my last fight in six years. I actually ran into an old class mate of mine, we had fought all the time (not that he was a bully, we just did not get along) and we greeted each other in open arms, he had involved himself with a crowd that I would cross the street to get away from, but miraculously we were now friends. It's so funny when you don't realize how much people grown up, until you do