Audiences (known in our house as the Noel Edmonds audience from his "House Party" show) who clap in 4/4 and speed up despite the song being in 3/4 and slowing down....And people who think they can still sing when drunk. I know 2 people who do this, and they are both 'performers' rather than just floor singers - they try to make money out of it and still insist on drinking on stage... They get flatter and flatter and can't hear it... I cringe for everyone then!
Oh, and being in the same house when the piano is being tuned.... AAAAARRRRRGGGGHHHH!!! Torture.
LTS