To everyone now fretting about coming to the US and not knowing who/how to tip:

For every one person who insists all Americans should tip [insert laundry list of 100 jobs here], a bunch of the rest of us only tip waiters, delivery people, baristas, and only when someone is our regular [x job] or does an outstanding job, and there are plenty of people who don't even tip under those circumstances. Trust me, you'll be totally fine.