The reader has certain rights. He bought your story. Think of this as an implicit contract. He's entitled to be entertained, instructed, amused; maybe all three. If he quits in the middle, or puts the book down feeling his time has been wasted, you're in violation.
Larry NivenThere had been a popular joke on Freedom, started by a man named Calder. Looking down from space, he had said, the dominant life forms on Earth were obviously the cereals and other grasses. They occupied all the most desirable and fertile land; and they had tamed insects and animals to care for them. In particular, they had domesticated the bipeds to nurture and cultivate them and to save and plant their seed. Now, watching the farmers, Alex could easily imagine that they were worshiping and genuflecting before their masters.
Larry NivenFor each human being there is an optimum ratio between change and stasis. Too little change, he grows bored. Too little stability, he panics and loses his ability to adapt. One who marries six times in ten years won't change jobs. One who moves often to serve his company will maintain a stable marriage. A woman chained to one home and family may redecorate frantically or take a lover or go to many costume parties.
Larry Niven