Ugh, retail. Did that for ten years. My condolences.
I work at a winery, so summer is our busy season, not Black Friday/the Holidays, but we ARE doing more outside events and promotions and things, and guess who is the outside events monkey? Yeah, that's me. If there's a person pouring wine samples at a farmer's market or convention or holiday food and crafts show, that's me. I like doing it all right, and it's good practice for someday having my own art table at a convention, but it is exhausting.
No worries, though. After multiple Christmases behind a cash register, I'd never dream of abusing a retail worker, especially this time of year. I'd tip them if I could.