The contrast between the Nickleby family’s happiness and Ralph’s misery reinforces the novel’s argument that Ralph’s selfishness is ultimately self-defeating. While Ralph pointedly only cares about himself, that kind of self-interested behavior actually precludes the possibility of happiness because it alienates the people who might otherwise form relationships and become close to Ralph. Nicholas, on the other hand, doesn’t have money, but he makes friends and treats others with loyalty, which leads him to have a flourishing and fulfilling life.