One of my favorite chunks of The Literature of Hope in the Middle Ages and Today: Connections in Medieval Romance, Modern Fantasy, and Science Fiction, by Flo Keyes:
Action, not introspection, dominates. The reader is not told how to act; he or she is shown. The hero is not proposing a plan for the future; he is carrying it out. If a science fiction writer had a man wake up to discover he had been turned into a giant cockroach, as Kafka has Gregor Samsa do, the story would not focus on the cockroach’s loss of humanity, his sense of alienation from his family, the resurgence of gumption in the previously passive family members, and a wasting away into death to get himself out of the way. Instead, the reader might expect to hear the human/cockroach thinking something like, “Wow! I’m a cockroach. No insecticide known to man can kill me, maybe not even nuclear radiation can kill me. I can get into all kinds of places humans don’t want me to be, and I can walk on ceilings.” Then the cockroach would tumble out of bed, squeeze through one of those impossibly small spaces no one can believe a cockroach can fit through, and set off to save humanity from itself (and maybe make the world a better place for cockroaches of all sizes, too).
I don’t think there’s anything else to say, really. But in the end, I think that’s a pretty succinct summary of why I didn’t like METAMORPHOSIS at all. Wimpy Gregor just laid down and died. What’s that about??