This one is what gets me the most.
Back when I had a small supermarket job I wasn't even allowed to defend myself when a customer would threaten me. Instead I would have to do exactly as they said .
Nowadays i'd just throw some hands if that happens.
Oh yeah, and the fact that I had to drop my current work everytime a customer asked for a product. Which resulted in me going to the stacked warehouse, finding the product and going back to the story, only to see that the customer doesn't care/already left or made up his mind and wants me to get another product from the warehouse. So frustrating!
Glad I stopped doing supermarket jobs ages ago.