My biggest pet peeve is role playing with someone who starts off pretty decent then halfway through the story (when you're playing the male) their character is suddenly a sexual predator that has sex with your character and the next thing you know their character is pregnant and suddenly the actual plot of the RP is lost and it becomes a weird episode of Leave it to Beaver.

That is my #1, biggest pet peeve ever!!!!
Because I'm all about plot progression, character development, twists!
I don't want my my assassin who's hired to kill your character to suddenly evoke a daddy and spend his time changing diapers and singing Hush Little Baby.

):<