Since we're also sharing sayings we love:
"You shut your mouth when you're talking to me"
I'm a huge fan of this one because initially it makes one sound like a complete jerk, but because it makes zero sense at all it loses all weight as an a**hole remark.
I think this (or something like it) came from a Jim Butcher novel:
"I could count all the reasons on the fingers of one foot."
Terry Pratchett (again, something to the effect of):
"I'm not afraid of heights, I'm afraid of grounds. It's the grounds that kill you."
And since the day it popped into my head I've been annoying folks with this one:
Me: I've got good news and bad news. Which do you want first?
You: Give me the [good news/bad news] first.
Me [you answer "good news first"]: The good news is there's no bad news.
Me [You answer "bad news first"]: The bad news is there's no good news.
Another annoying one based off of the phrase, "well, if it makes you feel any better you should [xyz]":
Me: Well, if it makes you feel any better, you should do it.
You: Do what?
Me: Whatever makes you feel better.
Needless to say, neither of these will make you any new friends.