It's really though to judge ones own material. Let's say you came up with some magic trick. You perform it for audiences and the audiences react really well to it. They love the trick. Most of the time that leads to the assumption that the trick is really good. But that doesn't have to be. It could also be that the reason the audience reacts so well is not the trick, but the performer.
Nevertheless the performer fails to see that and releases that magic trick and wonders oh so much that the rest of us fails to deliver that little performance uniqueness that makes the trick work in the originators hands. Naturally he will get some "honest" reviews that aren't nice. Looking at you Andrew Mayne.
Why do I care about that? Well I know of someone who doesn't want to fail. Crap it, I said too much.