Ever get to talk to a celebrity? Were they stuck up?

Who is the most famous person you have even met and got to talk to? Were they nice to you or mean and stuck up? --- I once met Robin Williams and he was a total A*s-hole to me. Stuck up, rude, condescending...ect. Maybe he was offended that I didn't ask for his autograph. I did however compliment him and he made fun of me for doing so..."Oh, this must be a big day for you." He said. (Among other rude and mean things.) What was your own experience like with a celebrity? Good or Bad?