Not that I've had many!
But Christian Bale was in London 'itsu' a few months back.
He was buying something but I'd just picked it out of the chilled section. I saw he went to reach out for it at the same time so offered it to him, as I liked something else anyway
His response? 'You've touched it. Why would I want it now?'
I was really shocked at how rude he was!