My biggest pet peeve is when I greet a table and ask for their drink order, and I get the response of "HOT WINGS!" (it's always wings, why is it always wings? It's never "CRISPY GREEN BEAN FRIES"). My favorite way of dealing with it is to then ask "Frozen or on the rocks?" and then when they look confused very sweetly say "It was a joke, I asked what you wanted to drink and you ordered your appetizer. What can I actually get you to drink?"
One of my coworkers is a big fan of making rude people wait. If he greets a table and no one even looks up to acknowledge him and just sits staring at their menus or talking amongst each other, he'll just say "looks like you need some time, I'll be back in a little while when you look ready" and then spend the next 5 (or more) minutes focusing on the tables who actually care to talk to him.
It's pretty common at my store to get leftover change as a tip. You know, people leaving a $50 bill for their $49.32 tab (or, more commonly, something like $87 in cash on an $86.something tab). Our standard response, as the group is walking out, is to say as cheerfully with the biggest grin as possible "Bye guys! You're very generous, I appreciate it!"
It's petty, but it keeps helps us feel like we're maintaining some semblance of dignity.