There is a stage you reach, Deagle thinks, a time somewhere in early middle age, when your past ceases to be about yourself. Your connection to your former life is like a dream or delirium, and that person who you once were is merely a fond acquaintance, or a beloved character from a storybook. This is how memory becomes nostalgia. They are two very different things - the same way that a person is different from a photograph of a person.