Anne Murray in the late 80s - she was drunk and got into a verbal altercation with a couple of hecklers to the right of the stage. Then she told us that if we'd really clap loudly she'd dance for us. I think that is when I left.
My worst was the night I got drunk in self-defense up at Challis in the Custer Saloon. Last song was Tennessee Stud and the guy who requested it and I both passed out at the same time. To my credit I fell backwards and did not injure my faithful guitar.
Steve
The other side of this is I've only had the one negative experience in seeing folks. But then I've only been to 3-4 concerts in my life.