My husband worked with many celebs in Hollywood when we lived in LA. Most were very nice. I can't really comment on the the ones that weren't as nice. My point was mostly to say that most of them were nice.
The only rude experience I have witnessed was at the Burbank airport. Bonnie Franklin and I had apparently been on the same flight and she was getting her luggage at the same luggage conveyor. She was very loud, complaining about the flight and the stewardess and the pilot, dropping a lot of F bombs, not caring that little kids were around, etc.....
She wasn't rude to me personally, but it def. made me think less of her.