Doesn't have to be uproarious humour, gentle wit and interesting anecdotes can be just as engrossing (think Dougie Maclean).

Basically, with most people, if they themselves find what they have to say funny/interesting/weird etc. then when they say it, that feeling is conveyed and the audience appreciates it.

I've seen comedians and performers going through the motions who were a lot less in tune with their audience than some performers who just tell you where the song came from and put it into a historical context.

I do like Spiers and Boden's idea of casting ballads as a Hollywood movie; I've stolen that one a couple of times.