Never had an embarrassing moment but my friends have. 2nd time snowboarding for him, he didn't get off the lift at Boreal (he claims the other two riders prevented him from doing so) so it turned with him still on it, they had to stop the lift. And he had to be helped down.
Second time was on bottom of Peak 9 at Breck, one of those small but very fast chairs. Two guys, weren't prepared, literally scooped them up. Once bounced off right away, the other was hanging onto the chair while it was going up, waiting for it to clear the ramp. After that he dropped off. Hilarious stuff.