In F. Scott Fitzgerald's novel, The Great Gatsby, the protagonist—Jay Gatsby—makes choices that are not morally sound.
One of the earliest images the reader gets of Gatsby is the description of his roots. He comes from poor farming folk and is ashamed of who he is because of who he is related to. Wanting to improve one's life is not a bag thing, but Gatsby does not make a place in the world in an ethical fashion.
Knowing that he cannot hold the materialistic Daisy without wealth, Gatsby becomes involved in drugs, and it is in this immoral atmosphere that he improves his station in life. He cares not for others but of himself, and how he can win Daisy, even though she is, by now, married.
This brings another moral indiscretion to light: Gatsby is obsessed with Daisy. Even knowing she is married to another man, he buys a home across the bay from hers, and tries to get her to come to one of his parties.
Nick Carraway, a cousin to Daisy, is an intelligent, realistic man. He comes to know Gatsby well. Gatsby uses Nick to get him to invited Daisy to one of the gatherings at his house. Nick sees things about Gatsby that Gatsby may not recognize about himself or care about. Nick realizes that:
...Gatsby is both a racketeer and an incurable romantic, whose ill-gotten wealth has been acquired [to gain access into the] moneyed world of Daisy's circle.
As Nick is the "moral center of the book," it is through his eyes that we most clearly see Gatsby for who he is.
Gatsby has exhibited immoral behavior in the way he has made his "fortune," in that he is pursuing the love of a married woman—willing to do almost anything for Daisy—and using Daisy's cousin to get close to her. Gatsby can see nothing else in life but his obsessive desire to finally win Daisy.
Gatsby's lost sense of what is appropriate is seen in his actions. His obsession blinds him to all else.
This obsession is characteristic of a dreamer like Gatsby, who loses a sense of reality but rather believes in “a promise that the rock of the world was founded securely on a fairy's wing.”