I always edit my work many times before I show it to anyone else, knowing myself too well to assume I did it right the first time. Then I send it off and VOILA! someone wants to publish it. Yay!
Then come the edits.
As I read the editor's comments, I think, "Yeah, she's right. I should develop that character more," and later, "Wow. It's true, I left that chapter hanging." Farther on I think, "I really do need to clarify that plot point. She got me there."
What all this means, of course, is work: fixing, fixing, fixing, and then reading for continuity and then more fixing and more reading.
Sometimes (just for a little while) I think, "Why doesn't she get this?" Then I remind myself that this person reads for a living. If she doesn't get my meaning, what are the chances my readers will? A good editor (like the one I currently have) makes a book better, and for that any author should be--indeed, has to be--grateful.
Even when it means more work.