What's the biggest dick move you've ever done to a kid and felt no remorse afterwards?

While working at a Subway one night this kid comes in and orders a footlong. The entire time I'm trying to take his order he mumbles, sighs, looks/walks away, keeps saying "I dunno" just being a brat. When it comes time to pay he smiles at me with this little shit grin and says he doesn't have enough. He's close but off by about 40 cents. So I said no problem little buddy let me just ring that in as a six inch. He beams triumphantly that his short change plot worked! But alas I snatch the sandwich back, split it in two, hand him half the sub with his change and toss the other half in the trash. Felt very satisfying.

Edit: First off, front page sweet! Second I am loving the stories. Kept me laughing all morning. Thirdly some haters have been saying we are jerks for picking on kids. I say kids gotta learn!