Some of the carry out places I frequent have tip jars, and the credit card receipt has a line to write in a tip. I always feel awkward when the guy at the register looks at my receipt and I didn't tip. But I don't see why I should be tipping - I walked my ass over to pick up my own food. Any work they did should be included in the price of my order, no?
mesmerism! presidential assassinations! circuses on fire!