Nick Carraway, who declares himself "one of the few honest people that I have ever known" in Chapter Three becomes "a bad driver" at the end of the novel. Through his association with Daisy and Tom Buchanan and Jordan Baker and Jay Gatsby, Nick becomes "alone in the unquiet darkness" of moral ambiguity. For, he is associated with people who have extra-marital affairs, who have cheated, and who lie about their past. His own behavior is questionable in Chapter Two as he rides in the elevator with Mr. McKee, but is later, after an omission of words
...standing beside his bed and he was sitting up between the sheets, clad in his underwear, with a great portfolio in his hands.
Then, Nick returns home on the four o'clock train. In Chapter Four yellow imagery connotes the opulence and decadence of those who attend the parties held at Gatsby's place in the West Egg. Nick states that he "was on my way to get roaring drunk from sheer embarrassment" when Jordan appears. With her, then Nick saunters around Gatsby's garden where they talk with the guests. He observes Gatsby's show of opulence, and he begins to enjoy himself as "the scene had changed before my eyes."
Yet, when he works, Nick feels "a haunting loneliness." Much like those with whom he associates, Nick has become frivolous. He feels only "casually sorry" for Jordan, who is dishonest. At Gatsby's party, he records the names of the guests on a railroad timetable, names of such sordid characters such as Ripley Snells, who comes "three days before he went to the penitentiary." But, despite the hedonism he witnesses, Gatsby comes "alive" to Nick,
...delivered suddenly from the womb of his purposeless splendor.
Nick becomes involved in Gatsby's plan to reconnect with Daisy after five years, acting as a panderer, just as he has been involved in the affair of Tom and Myrtle by being in the outer room while the couple are in the bedroom. Clearly, he has become part of a tawdry society with a meretricious appeal that is both "enchanting and repellent" as critic Casie E. Hermanson observes. With equal ambivalence, Nick finds Gatsby deserving of scorn in his illegal activities and his subterfuges, but at the same time, he is admirable in his idealism and heroic efforts to protect Daisy after she hits Myrtle Wilson--
He...turned back eagerly to his scrutiny of the house, as though my presence marred the sacredness of the vigil. So I walked away and left him standing there in the moonlight--watching over nothing.
And, so it is this ambivalence which makes Nick become a "bad driver" in the end, one who "drove on toward death through the cooling twilights." His complicity with Tom and Myrtle, Daisy and Gatsby are what make him a "bad driver."
Nick Carraway has come to East and West Eggs as an ingenuous Midwesterner. His exposure to the lies and deceits of the "careless people" like Daisy and Tom Buchanan causes Nick to question some values; but at the same time, he admires Jay Gatsby, stating that Gatsby is "worth the whole damn bunch put together." Through his association with these people, however, Nick has been affected, causing him to become frivolous and one who manipulates truth. However, Nick will return to the Midwest, "the green breast of a new world," the significance of the past, where there are yet values, and not mere materialism and amorality.