My friend Dan Milstein pointed out this post to me over at the Newbie's Guide to Publishing, about the difference between confident writers and delusional writers. It's a great post and the discussion that follows is worth reading, too.
I hope, of course, that I'm confident writer, not delusional. Though as Konrath points out, delusional writers will not know that they're delusional, so instead will consider themselves confident. So I guess I don't really know. I might be a little bit of both.