Quite some years ago I went to see one of the doyens of the British folk scene who was doing a tour of small venues with 2 or 3 musicians, I forget which. She'd decided to play only recent self-penned stuff of a singularly appalling quality, really banal stuff that sounded like it was written for the cast of Playschool.

Looking round the room you could see the pain on the punter's faces as the applause became less enthusiastic until people more or less gave up clapping. I don't believe she's ever done anything as bad before or since. Though I don't consider myself remotely folk police I did think I'll never get that hour back. IIRC correctly she was booked for 90 minutes but everyone gave up long before.