Send a half-eaten entree back
"Oh, this is overcooked," you say, as you slide a half-eaten steak and missing sides over to the server. Was the other half medium-rare?
Blame the server for everything
You are aware the server didn't make your food, right? Or set the hours of operation? Or price the menu? Or clean the plate? Or forget to put a gluten-free option on the menu (seriously, enough with the gluten!)? She's also not the complaint box. Direct your rage elsewhere, Dr. Banner.
Leave literature of any kind
A pamphlet about the virtues of living a Godly life might be enlightening, but pamphlets don't put money in the ol' tithing basket. And nobody wants to see your post-hardcore slowcore band, so save that flyer for a telephone pole.