I had a guy troll me on LoL once. We were both working the bottom lane and he kept getting himself killed (early in the game). Blamed me for it, even though he was rushing in head-long. Apparently he knew another player on his team and kept asking that guy to report me

We finished the game, I had a much better KDA ratio than him, coincidently, and I ended up reporting him. Don't think anything happened and I pretty much quit playing LoL after that.
I also had a guy just the other day bitch at me and a couple other guys on TF2. Complaining that we weren't team players. Funny thing was, I wasn't on his team! lol. I told him so and he apologized. I guess some guys get so worked up they forget who they're mad at and take it out on everyone.