Nick ends up, as was the case through most of the story, with mixed feelings towards Gatsby, partly feeling sorry for him and partly admiring his never-say-die attitude and optimism.
Nick certainly felt pity for Gatsby and the way his life played itself out. Nick had come to understand that Gatsby had never had any realistic chance to win Daisy, that the charade of being the incredibly sophisticated and wealthy easterner was exactly that - a charade, an act that Gatsby kept up to prevent those around him from discovering the truth.
And yet, Gatsby had always pressed onward. He never gave up, because he always thought this would work out better next time.
Gatsby believed in the green light, the orgiastic future that year by year recedes before us. It eluded us then, but that's no matter-tomorrow we will run faster, stretch out our arms farther...And one fine morning-
In the final passage, Nick returns to the deep admiration he expressed for Gatsby in the opening pages of the novel. At novel's end, he has just met Tom in the city, and while he finds himself unable to forgive Tom for all that has happened, he recognizes, with some contempt, that Tom feels "entirely justified" in how he has behaved. What then follows is Nick's famous statement characterizing Tom and Daisy as spoiled children:
Careless people . . . they smashed up things and creatures and then retreated back into their money . . .
In contrast to this "foul dust," as Nick characterized it at the beginning of the book, Gatsby stands as a tragic hero, pursuing a dream impossible to realize with grandeur, pathos, and grace.
In the novel's last two short paragraphs, Nick affirms Gatsby as a dreamer and believer—beginning with the third-person singular statement "Gatsby believed." Interestingly, though, he immediately switches to using the first person plural: "us" and "we." Gatsby becomes the symbol of all who dream, all who yearn to reconstruct an idealized past, no matter how hopeless the task:
It eluded us then, but no matter—to-morrow we will run faster, stretch out our arms farther . . . And one find morning—
So we beat on . . .
Gatsby becomes hope writ universal: he encompasses Nick and the readers and the American Dream too, all that persists and yearns and loves and works despite a cynical reality and a past that can never return. Nick finds in Gatsby the doomed but larger-than-life spirit in all of us who still retain some innocence and idealism.