Worst thing you have ever done...
Or thought for that matter. Here's mine:
There was a kid who had some control/domination issues who used his rather cumbersome girth to intimidate and control others. Due to my short stature, I was one of those. Then his father died and he did something that really pissed me off--I was asking two kids about why they were doing something (as it didn't make any sense) and they explained it to me. Unfortunately, I didn't really understand their reasoning until later (it had to do with using a letter as a placeholder for something they were painting and the letter they used created a spelling error) and I asked again. The beast kid grabbed me by the shoulders, pushed me against the wall, and started screaming at me for being a moron. I looked straight at him and thought, "I am so glad your father just died."
I suppose that makes me a bad person, hun?