"I don't in the least know how to set to work to write, and I begin by expressing only the hundredth part of my ideas after infinite gropings. ...For entire days I have polished and repolished a paragraph without accomplishing anything. I feel like weeping at times. You ought to pity me!" Gustave Flaubert to George Sand.
The George Sand-Gustave Flaubert Letters, free on Google Books. The letters are beautiful, too.
Interesting that Flaubert compares the novelist to God: "I even think the novelist hasn't the right to express his opinion on any subject whatsoever. Has the good God ever uttered it, his opinion?"