Doubt.

I sent Kate my first draft of my first chapter last night, and ever since I hit SEND I've had all these panicked misgivings about various approaches I took, or decisions I made, this in spite of months of thinking, crafting, planning, re-tooling... Urgh. I can't imagine at all how it could be possible to really feel that you've ever finished something. I could substitute word for word, or approach for approach until the end of time, and the resulting chapter would swell and shrink, ebb and subside, in and out, like a breathing creature.

Oh, and? I quoted Jerry Seinfeld. Someone give me a doctorate.