Could you give info about decay of american dream in the great gatsby?

The novel being set directly after WWII re-emphasizes this theme. The young Americans returning from war had seen humanity its most brutal. This begins the shift in thinking about the American dream from one of happiness, freedom, and individuality, to the more materialistic goal of acquiring wealth. All of the major characters show this "decay." Tom, who has had money for so long that he feels above the rules that govern society. His blatant affair with Myrtle, his abuse of her, his racism, all show a decay in values. Gatsby has completely disregarded morality in his pursuit of wealth to obtain Daisy. Daisy, who disregards her love for Gatsby and chooses Tom for the easy, but empty lifestyle that he can provide. Jordan Baker is willing to cheat to win her tournaments, demonstrating that even the simple American value of fair play has decayed.