If you've really loved a book, or a movie for that matter, really loved it, what you want is that same book again, but as if you've never read it. And when you get something unfamiliar, you feel betrayed.
Before there was any talk of a movie, people would sometimes ask me what actors I would imagine playing these characters. And the only thing I could ever say is: I have such a clear idea of these characters that they'd have to play themselves.
The only difference was one of them was trying to make a perfect cake and one of them was trying to write a great book. But if we remove that from the equation, it's the same impulse and they are equally entitled to their ecstasies and their despair.