Probably not the nicest thing, but when it got time to leave my tip, I paid with my debit card and added the tip of $1.50. Below the total I wrote, "Your original tip was $3, but I'm giving you half and the rest will be distributed randomly to another person."
I have family who have waited tables for a living, so I know it's not right to take things out on the wait staff, but in this case, somehow I feel justified, and the $1.50 was around the 15% range. But this is the second time in a few months that I've docked tips because of ignorance and intolerance. I boycott Pizza Hut now because the last time I ordered delivery from there, I waited way longer than I should have had to for the food to arrive and when it finally did, some 40something grungefest was standing outside the door with my order. He seemed friendly enough, so I signed the charge slip and added a $4 tip.
As I'm handing the slip back to the guy, he says "Wow. this is much better than the order I delivered a few floors down from you." I say "Oh yeah?" and Mr. Too Old To Deliver Pizza for a Living says, "Yeah, down there, I rang the bell and this swishy gay guy answered and says "ooh aah you're finally here!" and while saying this he's making girly voices and limp-wristing one of his hands.
I just look at the guy stone-faced, and say "Oh, let me see what I handed you. I did something wrong." He gives me the ticket back and I strike through the $4 and put a $1 in it's place. I hand it to him, take my pizza, and as he's saying "Thanks" (unaware of what I'd done), I slam the door in his face.
Get some couth, people! Seriously.