An English author, Sir Arthur Quiller-Couch, coined the phrase “murder your darlings” to describe a good editing process. I’ve had to murder a lot of darlings while shaping my first draft, and I can only imagine how many darlings will meet destruction as the thing gets polished.
It’s hard! Especially when the darling in question is really–well, darling. Well-written. Poetic. Touching. A sentence, or paragraph, or even a chapter, that is wonderful writing but doesn’t belong where it is.
The chapters I wrote, one at a time, over the last two or three years contain a lot of writing that has to stay out of the book. Not because it isn’t good. It is. But the book has to have a story arc, and the content has to serve the arc. Not to mention issues around word count.
This week I cut the first chapter of the book. Just cut it, outright. I slipped a little exposition into what was Chapter Two, but all the writing from the previous Chapter One is gone. The book now begins in a completely different way.
Oh, darling. I’m so sorry.
Lori Lynne Armstrong 
I’ll just say that I really loved the draft I saw, as is. But you are right, there are always decisions to be made around editing and they are painful.