My agent once did a rant about bodily functions here: http://pubrants.blogspot.com/search?q=bodily
At the time I thought she was just being sensitive, and maybe I'm now being sensitive too--but there is something about reading certain words that makes them much more visual than when they are spoken. Snot is one of them.
Awhile back I was reading a romance and on several occasions while the MC was crying, the hero would pull out his handkerchief and instruct her to "blow"--Talk about ruining a sweet moment as well as making the MC seem about five years old.
So just for the official record: If I see snot mentioned in any book when it is not meant to be 2nd grade humor--I'm chucking it across the room.
What words or phrases or bodily functions have you read that really grossed you out when they weren't supposed to?