Oh my god, I wish that someone could have told this to me when we were starting out. I was getting a sense of this a few years ago, but Ira Glass says it better:
Nobody tells this to people who are beginners, I wish someone told me. All of us who do creative work, we get into it because we have good taste. But there is this gap. For the first couple years you make stuff, it’s just not that good. It’s trying to be good, it has potential, but it’s not. But your taste, the thing that got you into the game, is still killer. And your taste is why your work disappoints you. A lot of people never get past this phase, they quit.
Via Daring Fireball