It's been suggested that we write first drafts with our hearts and subsequent drafts with our heads. It's also been said that first drafts are crap. Likely, both are true.
When I start a new book, I try to keep that in mind. I usually know the beginning and end, but the impetus to write the book is nothing more than a series of images. A long way from crafting a novel.
It feels like moving to a different city and starting a new job all at the same time. I stagger from scene to scene, hardly knowing my way around, and spend most of my time with strangers. It's so uncomfortable, I end up focusing on editing to give my fingers something to do. But if I stick with it, I'm rewarded with new friends and a deeper insight into their lives. What's a bunch of badly written chapters compared to that. I can polish later. But nothing can replace living in the story.
Better to finish the first draft. As for the rest, that's what rewrites are for.