I've always thought it must be challenging, to say the least, to have any type of customer service job in a store. Usually, any job in which you have to interact with anyone who walks through the door isn't an easy one.
A few years ago, a grocery store cashier told me he had to censor himself when dealing with a rude customer. According to him, the customer said, "Oh, I forgot to get a 20-ounce Pepsi. You! Go get me one!" she snapped at him.
The cashier told me he kept thinking to himself, "Don't say what I'm thinking..."
A few weeks later, I noticed that he was no longer there. I wonder if he told a customer what he was thinking or resigned before it came to that.