Fast food workers get a bad rap. They are already making minimum wage, and there’s talk that burger flippers and cashiers will be replaced by robots and machines in the future. And, it’s one of the toughest customer service jobs on the planet. The most famous fast food joint, McDonald’s, is one of the world’s biggest employers, so you can be sure that they have their fair share of customer horror stories. If you want to piss off a McDonald’s employee, just do any one of these 19 things that annoy the shit out of them.