One of the many reasons I left the USA. Too bad US-Americans are so used to tipping 20% they even do it when traveling... giving the rest of us a reputation as being suckers.
Yes, one of the MANY cultural reasons. One less thing I have to think about when paying for food. There's honestly too many reasons to list: cost, safety, food, transportation, work life balance, education, being near family, and to see more of the world.
"Guilt" is an exaggeration, but the human behind the machine might care. It's a tiny inconvenience all things considered, and more of a principal than a practical issue. It helps tip the scale of where I'd rather live.