First, remember that The Great Gatsby is written in first person and all every event of the story is depicted through Nick's eyes.

Nick Carraway is a fucking dog.

Why did Gatsby decide to name his dog Nick Carraway? I'm not sure. One thing is for certain though, and that is that Nick is adopted by Gatsby when moving into his "new home" in West Egg. He lives in a doggie house in Gatsby's back yard. He states that his home is much smaller than that of Gatsby's and that Gatsby must be very wealthy. But throughout the story, everyone is wealthy to Nick; therefore, no one must be. Gatsby does not live in a mansion as Nick makes it seem and neither do the Buchannans; everyone in the story lives in relatively normal-sized homes which are inflated to Nick. And no, Nick does not meet Gatsby for the first time at a party. He is imagining this because he is a dog who is unfamiliar with his new owner at the time.

Why is Nick the moral center of the story, while everyone else (the humans) are corrupt at heart? He's a dog; he does not do wrong. Nick never goes anywhere by himself and has to be taken places by his owner and by the Buchannans, such as Tom's apartment in the City.

More questions are raised than are answered by Gatsby's incessant dubbing of Nick as 'old sport.' However, it explains why Tom gets pissed when Gatsby calls HIM old sport. Since this is what Gatsby usually refers to his dog as, Tom is actually being mocked by Gatsby. (Remember that this is the scene where Gatsby tells Tom off in saying that Daisy does not nor ever did love him.) Gatsby is either implying that Tom is no better than his canine companion, or that he is a 'dog,' which in this case most closely means 'player,' who cheats on his wife.

You know that they say. A dog is a man's best friend. Isn't it stated at Gatsby's funeral that Nick was his best friend? The evidence doesn't lie.

Sadly, none of the movie renditions do the story any justice for non-readers. No, not even the 1974 version starring Robert Redford. The main character is the wrong species in every single one of them for crying out loud. One simply cannot make a decent film interpretation of the book with an error like this.