What constitutes a “happy dream” for Christopher? How does it compare to a “normal” person’s happy dream?

Christopher describes a recurring dream, in which a virus has killed most of the planet and the only survivors are those who prefer to stay away from other people, like him. This is a happy dream. With all the other people gone, Christopher can do what he pleases and explore the world without worrying about other people trying to talk to him or touch him. Usually people have happy dreams that involve other people or new experiences involving other people. Imposed issolation is usually not what people consider "happy."

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