It took a long time to sort me out. So I try to be pretty gentle sorting out expectations that fall a little short of the actual experience.
One of the things I tell new writers that seems to be particularly shocking to them is that after you write it, you need to put it away and forget about it for awhile. New authors are long on enthusiasm, but often short on patience. They want the book in bookstores, and they want it as soon as possible. I get that. I had the same problem.
But I stand by the rule. Put it away. Don't look at it, and if you can help it, don't think about it. Usually, I suggest/instruct/plead with them to write something else while they're waiting. For good reason. Newly finished manuscripts are a source of pride, obsession, and a lot of love. You worked hard on it. You finished it. You've earned the right to fawn a little. But before you move onto editing, you better fall the heck out of love...and fast.
The best way to do that is to fall in love with something else.
In the same way that smokers cannot smell the odor in their clothing. (I smoked, it's true) an author who is still living inside their story cannot see it. The blinders are on. To get a realistic view you have to move out, quit smoking that book, and completely reboot your senses again.
You have to clean your pallet.
In the same way that you can't see your ex clearly until you've fallen in love with someone new, well you get it. Let the first book stew. Let the story percolate and stale. But if possible, write something new, something more brilliant and just as engaging. Love it. Then put it away and go back to the first book ready to kick ass and take names.
Editing will hurt a lot less too, if you've got a new shiny in a drawer somewhere that you know is better anyway.