The reason why is that American tipping is extortion.
Tipping should be an optional bonus that you give soneone for exceptional service.
In America, it is not only expected, but the servers will be pissed if they feel you didn't give them enough. They are entitled twats
The worst part is that servers will fuck with customers of the business over tips. What happens if someone doesn't tip and goes to the same restaurant multiple times?
Everyone always says things like servers will fuck with your food etc.
That's not tipping, that's extortion.
I tip often and tip very well, specially for people who go above and beyond their basic job duties to provide me additional service. I'm not gonna just tip some loser in America 20% of my bill because they feel entitled to it for doing the most basic duties of their job requirements
I do tip some people in the US, but only places I plan to go back to or people that give me really good service.
I remember going to a diner once and the annoying chick just kept coming over in 2min to check on the table and interrupt our conversation. That is not good service, it's annoying as hell.