When I was about 13 or 14, I revealed to my WoW friend (who I'd been playing with for months) that I was a girl and within a day he went from being my cool friend to someone who was offering me raid gear in exchange for talking dirty to him through Ventrilo.
Nearly 20 years later and I refuse to let anyone in on my gender. It's dehumanizing that we can't even play a game without being harassed.