People do seem to forget their manners in places where they are being served, either supermarkets, restaurants, bars, etc., perhaps they think they pay for such a service so it should be available without a 'please' or 'thankyou' being necessary.
It is always necessary.
When I volunteered in a charity shop I was shocked at how rude customers could be when I serve them on the till. I would always start with a smile and a 'hello', nothing more unless the customer spoke to me, but some would simply throw their purchases in front of me and continue talking on the phone or to whoever had come in the shop with them, treating me as invisible. One customer asked I would wrap what she had bought, I said we don't do wrapping, and the customer then proceeded to swear at me until I called the manager who told her to leave. I was so shaken I refused to go on the till again preferring to help in other ways. And this is in a 'charity shop', goodness only knows how rude/hostile some people are in larger retail outlets/supermarkets.
Good for the supervisor for reminding the customer about her manners in the OP. Luckily she didn't get a mouthful.
I really despair when I see how rude and inconsiderate some people are.
