I have a Frank Carson CD, and the songs are only about 80% of the recording, the rest being interspersed jokes, while the accordeonist carries on playing. It's a live recording, probably in a pub.
I'd never put it on if I wanted 'serious,' but when I want cheering up, it's great. Like R_Tim and Leadfingers say, you need an audience.

I'll go along with Joe_F about Lehrer and F&S, too.