"It isn't supposed to be good, it's Art."
Sometimes good isn't good enough. Sometimes just being in tune, and knowing the song, or knowing how to draw, or doing what everyone else expects you to do, or is already doing, is just not good enough. Sometimes simple competence isn't good enough.
Sometimes being really bad can be really good. Or not. It all depends. How to get to the transcendent, the amazing, the transformative, the unexpected, the better than good?
There are a million ways to go, a million ways to fail, and it's hard to tell when you fail, and when you succeed. The doing of Art is a method without method. Really, I think it's true, there are no rules.
So if they tell you it's bad, that you can't play, that you don't know how to draw, you don't know what you are doing, that you certainly aren't doing Art - you might be, you could be... or maybe not... it's just not obvious... Art kind of sneaks up on you... or zaps you in the eyeballs, knocks you down... picks you up and changes you in some way...