One night at a gig, when The Who had just begun, Pete Townshend was experimenting with the feedback he got when he put his guitar near his amp. He accidentally hit the ceiling with the guitar, which caused an awesome sound that was cheered by the (small) audience. Pete tried to repeat that sound with such bad (or good) luck that he broke the guitar's neck. "No one cheered, in fact there was a terrible silence, a "this-guy-is-an-asshole silence, so i finished breaking the guitar acting as if that had been my true intention". On The Who's next performance there were twice as many people.
Pete Townshend thought he was lifting his now-famous Windmill move from Keith Richards, because Pete saw Keith doing it as the curtain was rising at a Stones show. Later, after Pete had made it his big move, he talked with Keith about it and realized Keith was just stretching out his arm before starting to play...