These comments are from observation at club venues which are generally more intimate and informal than "concert" appearances, leading to different audience expectations.

There seem to me to be two basic types of s/s attitude, which I've experienced from both professional and floor singers.

A) "I've written these personally meaningful/socially important songs and now I'm going to sing them."
B) "I've written these personally meaningful/socially important songs and now I'm going to entertain you."

Type A are the ones I'm less than complimentary about. Type B are the ones I listen to. An intelligent set-list using, if necessary Trad. and/or other writers material to achieve changes of pace and mood, will keep my attention. If the artist disregards my desire to be entertained, I'll probably have "gone for another pint" before the end of the third song.

In the end it's not just the song itself that determines if I listen to it, (as opposed to sitting through it). It's the performance around it and the "courtesy" of the performer that determines how much effort I'll make to appreciate it.

Note: I've known professional singers of type A whose songs I really disliked until I heard them performed by a floor singer. I'd simply not listened when I'd seen them live.

AndyG