Can't see where sing arounds/sessions come into it so lets start off by missing those out. Different animal.

Yes, but one sort of gathering feeds the other. The same people who populate our session and singarounds are also those who turn up in clubs - they aren't totally divorced and are part of the same overall scene.

I've also been to concerts (not folk) - at a rare old price - where the main act was substandard. It might have put me off ever seeing that act again, but it hasn't put me off concerts per se.