The rules for tipping have evolved over the years. Now, with grocery delivery, Uber drivers, Amazon drivers, carryout food, pet groomers, and on and on, it feels like there are more opportunities to empty our wallets.
If you're grumpy about tipping, it's probably because norms have changed. It has "become less discretionary, and the tipping percentage has also increased," says Shelle Santana, an assistant professor of marketing at Bentley University in Waltham, Massachusetts. Santana's research focuses in part on the psychology of money, and plenty of emotions are tied up in how we give money.
