How does the tragedy of Jay Gatsby lie in his choice of Daisy as the person to embody his dream?

Much (although not all) of Gatsby's tragic end is embodied in his obsession with Daisy Buchanan. Though Gatsby has spent the greater portion of his adult life loving Daisy, his love ultimately proves to be misplaced. For instance, after a steamy affair, Daisy chooses to stay with Tom Buchanan to retain her stability and reputation for respectability. Moreover, Daisy allows Gatsby to take responsibility for running over Myrtle Wilson, even though she was to blame. Even worse, Daisy doesn't come to Gatsby's funeral at the end of the novel. As such, Daisy ultimately shows herself to be rather shallow and lacking in substance, making Gatsby's love unfortunate indeed. As a matter of fact, we can see Daisy's lack of substance as symbolic of Gatsby's lifestyle/goals in general: like the shallow Daisy, Gatsby's dream of success is based on a meaningless materialism and lacks any real substance. In that case, Gatsby's obsession over Daisy is an embodiment of the tragic meaninglessness of his dreams as a whole.