There was no real "worst" for me. It was all a bunch of little things that caused me to stop playing online games. Like getting killed then camped WoW at lvl 30 for a good hour or so. And then Halo 3; I suck at this game, so I wasn't to keen of it in the first place, but the teamkillers and twelve year olds who think... far too highly of themselves, I just gave up on internet games. The first time I've gotten directly insulted over the net was by a message on youtube after my bro left quite the comment on one of their videos.