Well, I've known people who can sing epic ballads and tell stories that can last maybe 40 minutes, and hold the attention all the way. It's a different art from the ordinary singing, and the listeners need to be attuned to the idea that that is what they are there for. And not many people can do it.

Mistaking what is fitting for the time and place and listeners, that's a difficult mistake to get out of. You're launched into something, and you realise that's not the right thing to be singing, for all kinds of reasons. Is it better to push on through or stop? I think probably the latter. "I don't feel like singing that one right now - listen to this..."