What purpose does the opening statement serve?

In the opening statement, Fitzgerald establishes Nick Carraway as an impartial narrator, though he is not a passive narrator. Nick is inclined to reserve judgment, but he is not entirely forgiving. From the novel's opening paragraph onward, this will continue create tension in Nick's narrative. Despite the fact that Gatsby represents all that Nick holds in contempt, Nick cannot help but admire him. The first paragraphs of the book foreshadow the novel's main themes: the reader realizes that Gatsby presented, and still presents, a challenge to the way in which Nick is accustomed to thinking about the world. It is clear from the story's opening moments that Gatsby will not be what he initially appears: despite the vulgarity of his mansion, Nick describes Gatsby's personality as "gorgeous."