Ever Evolving Crap
No matter what your writing style or education or orientation (I just threw that in there) as writers we all go through the same self-loathing "This is crap!"
And that's a good thing.
I know you're thinking "How can writing crap be good?" It's not the crap you wrote but the fact you recognize your work to be subpar. We grow as writers, or we should. You first book sucks worse that your current crap. Your first draft is for shit but now that your MS has seen a few revisions, it's looking like a viable life force and not some bloody pulp you hacked through the first time around.
Crap evolves from "this will never see the light of day" to "holy bat shit, I might query this sucker!" And when you've polished your crap until it shines, then send it to CP's and let them point out the skid marks you left behind. Eventually, when it is all said and done, you WILL no longer have crap but a solid piece of work you are proud of.
So the next time you berate yourself for writing the yuck, pat yourself on the back and say "Good girl, you recognize this needs work. Now get on it." (If you are a guy you can still say "good girl" if it makes you feel pretty but I don't recommend doing so publicly.)