You’re grabbing a bite with your friends and the bill comes. You know you’re supposed to leave a tip, but nobody is sure how much is expected, or how to calculate the amount without pulling out your phone.
In the U.S., waitstaff, delivery people, and many other service workers are often paid lower wages with the expectation that much of their income comes from tips. Think of it as part of the cost of the service and a way to say thank you.