What do you like/dislike the opposite sex doing?

I'd like to know, just for fun, what people like in a girl or guy, as well as dislike (basically turn ons/offs). Also, do you have any strange quirks? Like, for example, there's something you just can't stand the opposite sex doing that seems normal or insignificant to others? Or there's something the opposite sex does that just melts your heart that seems weird to others?