There are very few things in this world that can make you feel as colossally stupid as line edits.
You find yourself thinking things like, "Can it be considered world building that parents are nonexistent and it's always Friday?"
And then you realize that you're a complete hack who never should have written a book in the first place.
And then you cry.
Eventually you work up the courage to open the document again only to find that your brilliant editor has pointed out that one of your characters is a complete doormat.
And then you cry some more.
You make some decent changes along the way and when you're finally done you realize your book is about a million times better than it was before.
And then you eat ice cream
Ah, the glamorous life of writers. Try not to be too jealous.