The two worst audiences are other players of the same instrument and yourself. Both are biased by the possession of too much information. The other players will always be comparing you to them and the countless other genius players they've studied all their lives, and you are YOU, too close to the topic to be impartial.
I was thinking this morning though, that a partial answer for
@Jazzaferri about how perfection can be summed up was something I witnessed years ago. A friend of mine was an engineer at Capital in L.A. I've told this story here before. A session was set up and Glen Campbell came in with his guitar. He chatted with the engineer and producer for a few minutes while setting up his gear. They ran the track and he played a solo over it. Nailed it in one take. I'm not a fan of country and the song wasn't challenging in the sense that some jazz tunes can be. Campbell's performance was so
musical, I was blown away. Structure, note choice, facility, not showy, just in the right places, all these qualities and more made me think he could have done 20 different takes and they'd have been as good. I thought then that it was as close to perfection as is humanly possible. In tech we speak of "
five nines" (99.999%). I'd rate Campbell at five nines. There may be an example of him somewhere that is less that excellent, but I'd bet 99.999% of his work fulfilled the promise of reaching an unbiased audience on multiple levels.
In order to qualify as perfection, the entity that produced it would have to be
infallible. It is impossible to be human or machine and be infallible. I include machines and algorithms in this, because it is widely known that algorithms are incapable of producing a truly random number. My definition of "musical perfection" is
the ability to produce music on demand that will accomplish the mission @aldevis quoted me on above. I've seen references to many saxophonists who got there and the first name that comes to mind is Michael Brecker. I feel confident that he, for lack of a better way to put it, would smoke in any context he every played in.
Boy, that was verbose. I am obviously less that a perfect writer!