In response to the OP - I'm sorry you had a bad experience. I've been on both sides of the counter there, and rudeness, no matter how frazzled, isn't acceptable. At the same time, I'll just bet that she was a last minute cover for someone else's flake-out/emergency, but it wouldn't hurt to let the manager know all the same.
Regarding the fabric stores - My roommate once worked at a Jo-Anns, and has any number of horror stories about the customers.
For example: she worked during the winter months, and therefore had to go out and collect the carts from the parking lot so they could be available in the store. While doing this one day (in January, mind you), a woman stormed out of the store and jumped into her car. She made as if she was going to roar off, then pulled up next to Roomie. She rolls down the window of her car to address the poor, bundled up cart jockey as follows:
Lady: "Hey Miss, excuse me"
Roomie: "Can I help you"
Lady: "What's your manager's phone number? I need to talk to her."
Roomie: (rather confused - didn't she just leave the store?) "Um, well, I'm afraid I don't know off the top of my head."
Lady: "Well you're just absolutely useless then, aren't you."
Lady rolls up her window and roars away.