I'm always pleased to encounter a true wit, however you are only halfway there...
Why don't you up the f### shut! lol
Spit in the eye? idk there no "Come back" for something that blatent
Nah, I think I'll just keep talking. LALALALA!
Ya know, I would, but my back...<br />
Granted, I just use that wherever applicable as long as it doesn't make sense in whatever conversation I'm having. It tends to make people shut up really easy lol
Walk away and let them win the battle for pettiness while you hold your head high knowing you won the battle for maturity.
Your face is just fine, but you will have to put a bag over that personality.