Sooner or later you have to stick a fork in and say it's done, and send it out to the wide, wide world without you.
The problem is figuring out when. If you look at a work and see no overt faults but detest the very sight of it, is that the reflection of a flaw you just haven't figured out yet? Or is just that you are sick to death of it?
It's all the more fun when you're cranky anyway and so could be dissatisfied with anything. Of all the evaluations of a work, the author's right after finishing it is probably the least reliable.