It's a topic that brings out my cantankerous old man persona. In the halcyon days of the late 20th century when everyone paid for restaurant bills in cash, tipping was a tolerable tradition. Throw in another $2 if you've got it, why not. You'd never expect the waiter to stand there and count out all the nickels and dimes for exact change, so you've got to raise the amount paid to the nearest round number anyway. Then we started paying with credit cards. If people were rational that would've been the end of tipping, but then if people were rational we'd still be paying in cash. After so many years of constantly seeing it done and occasionally even partaking in it, adding a tip to a payment made electronically still feels like a crime against nature.