One customer was ‘held responsible for their actions’ by a full-service shopper who felt it was their mission in life to teach them a lesson. What was this lesson about? Well, tipping. Look, people are awful, I get it. I was a waitress once for many, many years, where I met people from all walks of life. Some were kind, some were petty, and some were downright entitled human beings. Working in the service industry really gets your hatred for humanity going, but still, by law, you don't need to…