What does this have to do with writing and publishing you ask?
Well, I've noticed the same thing among unpublished writers. Those who I think are absolutely brilliant, think their writing sucks donkey bits. Those who think their writing is the greatest thing since Homer jotted down a little poem, write dreck.
Digging a little deeper what I find is those who get down on their writing are the same as those dancers who didn't think they were very good. They are perfectionists. Perfectionism is a good thing when it helps one strive to do better, perform better, write better. But, it's a bad thing when it strangles the writer and prevents them from writing, blinds them to what is good about their writing or in accepting the honest feedback that they are getting.
It's very rare to find someone who is objective about their own work. Yet, to write the best that one can write, objectivity is, in my opinion, absolutely necessary. Couple objectivity with perfectionism, the output will be amazing.
How does one get objectivity? Curiously enough, I don't know as I don't have it. I realized as I was writing this post that I probably fall into the "thinks her writing is good, but it's really dreck" camp. The last two people I showed one of my own stories to ... one that I was really proud of and thought was pretty good ... both reacted rather tepidly to it. I guess it's a good thing that I can see it in other's stories and decided to become a publisher, rather than bash on trying to become a published author myself.
By the way, I hear they are having a sale on objectivity this week ... if you're running a bit low ...