I was at a Cliff Eberhart concert (a "nice" formal concert venue) when someone's phone went off, and the guy actually took the call. Cliff stopped playing and waited... I think he was just starting the song... and the audience got really uncomfortable. The guy quickly finished the call and said...

"Hey, some of us have to work, you know."

Cliff's response, after a long beat...

"Bless your heart."

And the concert went on.