I recently (Like, three weeks back) was sent a message from another player during a game of Team Fortress 2 on Xbox.
This Engie's sentry kept getting destroyed by a Spy, so I was pretty much hanging around him, spy checking whenever someone came nearby. I'm still amazed at how bad the Spy was, because he always ran straight for the sentry, and was disguised as a Sniper each time. Around the tenth time I killed him I got a voice message from him. Apparently he was pissed at me for hanging around the sentry and defending it from him, and told me that real players run around. Since by that time there was another Pyro helping me defend, I decided that I should probably help my team get the intelligence, and headed over to the Blu base through the tunnel at the bottom of 2Fort. Where I encountered the same Spy disguised as a Sniper. So of course, I kill him. A few seconds later I get another message from the same guy, this time accusing me of cheating somehow. I write him back telling him that I'm not opening any more messages.
He flips out at that and starts sending me more and more threatening and vulgar messages, none of which I respond to. Eventually, after the thirteenth message he quits the game, although he joined another game I was in the next day and started harassing me again, except this time he was on my team and was following me around insulting me over the mic. It was funny as hell.