Also in the ROTFLMAO dept.... kidneygarten...!
How about the guy who comes up to tell you how to play? We had an expert come up (during a tune!) to tell one of the fiddlers to "play a third above the other guy". There was no stage in the pub, we were on the floor, so this fella could get his beery face right into ours -"play a third above the other guy". Jeez. We told him to go away.