[6stringmerc]

It might not sound like it but it actually is quite helpful - translated it means "you are not doing well at a very basic thing and need more practice" because if a guitarist, on stage, can't hit a G-C chord switch competently, then there's really not a lot of wiggle room. They...suck...and need to be shown ways to improve. A lot of times the self-esteem-based response will dismiss the criticism as 'being mean' or some crap when it's actually totally valid.

[sliverstorm]

Do they not know they blew the chord switch? It seems like they'd know that.

[abstractbeliefs]

Probably not - you're supposed to hone your craft through practice before you perform in the way that was described.

If the overall performance was poor, and something so basic was clearly an issue, then maybe they don't realise?

This is like a development candidate being poor at simple interview problems - it simply is the case that often you don't know what you're doing wrong until you've developed skill, but people around you saying you're doing great can suppress your desire to work on that skill in favor of rushing ahead to interview where you fall flat on your face.

[bsder]

The Open Mic D-Chord disagrees with you ...

(An Open Mic D-Chord is a D-Chord (D A D F#) where they don't mute the lowest string and thus put a really nasty sounding E note on the bottom of the chord)