The other thing that happens is less welcome: the hopelessness sets in. I can see the book as a whole now, and every single day, I struggle with the voices that are telling me it's not going to work, it's going to fail. It isn't about anything. I'm not good enough to pull all the loose ends together. I'll get to the climax and realize that it's a dumb climax. It's a mess and revisions won't solve the problems.
You acknowledge the voices, but you write anyway. This faith is performative. I believe in this book.