When i'm reading a great work of art, i don't know how it's going to end. Mediocre art has no surprises because it's fits the genre. The author created something for you to explore alongside the author. And sometimes you see something the author didn't see. It is part of the narrativea that the author unconsciously built allowed you to find. If an actor is not somehow telling a secret about themselves, nobody will be interested in their performance.