True, but you may not want to return and receive service from a waiter whom gets combative over how little you tip. As another person who has worked both front and back of house, I’ve seen and heard some pretty awful stuff.

This is particularly why I hate the new custom of tipping before even receiving service or food. You have to do some game theoretic dance to decide whether you’ll get bad service if you tip low up front vs get bad service anyways because they’ve already got your money.

In theory Yes. In practice, do that to a waiter and if they remember you next time, Good luck eating that food. Tipping is seen almost as an entitled benefit now but provided by the customers instead of employers. It is a lose-lose situation for the customer and employee because waiters get paid like shit by their employer while customer has to cough up the "tip" regardless of how they felt about the food and service.