Worst live performance by a big name: Dave Van Ronk at some club in New York at least 25 years ago. Got on stage nearly half an hour late. Did one song, then said "I gotta pee." Got off stage. Came back 10 minutes later and did two more songs.

Worst performance by an unknown: Three young louts who sang God Save the Queen, then reached into their back pockets and pulled out little British flags (Union Jacks) which they used as snot rags. I presume they were trying to be funny. Easy to do when you're in Far Rockaway, NY. At least they were cute looking.