Worst I hurt myself: Older, much larger cousin broke my leg by landing on it in a bouncy castle.
Injury that pissed me off the most: At 13, I loved jiujitsu and rock climbing above all else. At my last jiujitsu class before going to California to, among other things, go bouldering in Joshua Tree, I sliced my heel badly on the metal bottom of the dojo door that had about an inch and a half of clearance from the floor.
Shoes in general, let alone those super-tight climbing shoes, were out of the question for two weeks. I'm still mad. Of all the ways I could've got hurt, it was the fucking door on the way out that took me down.