I read that the real difference between short story and a novel is this: A short story is a pivotal moment in someone's life. It looks close at the details of that moment, warts and all, just before a big change occurs. Then the change happens and the story is over. A novel is more like a long trip that you take with someone you like and identify with. You invest more of yourself in the novel. It's a long vacation that you want to enjoy and you expect happy endings and noble people or the vacation is not as pleasant.
What do you think?