Jay Gatsby's obsession over Daisy Buchanan and his perception of what his life would be like with her clearly shows that he is not dealing with reality. For Daisy, Gatsby changes his name and denies his family, participates in illegal activities to get rich, moves close to Daisy and holds fancy parties in hopes of seeing her, and chases after her despite the fact that Daisy is married and has a child. He is living a dream and doesn't see the reality of his actions. Daisy is smitten with Gatsby but doesn't really have any intentions of leaving Tom. Tom is who society expects Daisy to be with; he is old money and of the same social stature as Daisy. Gatsby comes from a poor background, is new money, and not an equal to Daisy. Daisy leads Gatsby on, and we think she may leave Tom, but in the end, Gatsby's dream is not her dream. Gatsby's obsession is what eventually destroys him as he is unable to realize the nature of his passionate "addiction" to Daisy.
There seems to be something wrong with all the characters, Daisy in particular. They are all suffering from a lifestyle that is causing values and beliefs that don't help them become redeeming characters.