There is a difference between something being essential, and it being necessary. If you take your favorite book and strip it down to what is merely essential to tell the story, it would be butchery. The end result would horrify you. Essential is the bones of the story, but the soul lives somewhere else.
Patrick RothfussHumor is important for is pacing. If your whole book is just drama drama drama, it's going to wear down the reader.
Patrick RothfussChronicler picked up his pen, but before he could dip it, Kvothe held up a hand. "Let me say one thing before I start. I've told stories in the past, painted pictures with words, told hard lies and harder truths. Once, I sang colors to a blind man. Seven hours I played, but at the end he said he saw them, green and red and gold. That, I think, was easier than this. Trying to make you understand her with nothing more than words. You have never seen her, never heard her voice. You cannot know.
Patrick Rothfuss