people who sing usually believe the can sing. I can think of several on this and other threads, who I have either heard or seen, and who in my opinion would not get a turn if I was MC , yet they feel free to criticise others.
Of course my opinion could be flawed I may be a crap singer myself, who is to say.
As Burns said
"Oh, wad some Power the giftie gie us,
To see ourselves as others see us!"
john