For me, there is something that happens about 1/3 into the book that I can't describe as anything but divine. It's this miracle of creation that is beyond just me. Suddenly, I know what happens next and where the rest of the book is heading--without a doubt. I never expect it and it usually surprises me. I love it. This is why discovery writing is so organic. It flows and grows in a way that is unexpected, even to the writer.
...it also means I usually have to go back and rewrite the beginning to include all the foreshadowing that I didn't expect I would need. But it's worth it and I really enjoy the whole process.
How does writing work for you? How does your story evolve?