Gatsby's "Old Sport"

At first, I thought Fitgerald's use of the nickname "Old Sport" in The Great Gatsby was really annoying.  However, I have a theory for what the phrase may signify.  He only uses "old sport" when referring to Nick and Tom.  Gatsby looks at his dealings with these men as a game.  He befriends Nick just to get to Daisy.  Tom, to Gatsby, is simply a joke because, in his mind, Daisy never loved Tom.  Gatsby has the role of navigator which allows him to manipulate in order to get exactly what he wants.  He uses the infamous smile and his endless resources to shield people from his real intentions.  Unfortunately for Gatsby, he has not experienced failure in quite some time; therefore, he does not expect it, especially from Daisy.  However, when she says, "' I love you now--isn't that enough?  I can't help what's past...I did love him once--but I loved you too'" (Fitzgerald, 132), Gatsby has now failed, not completely, but enough.  I think this chaotic point in the novel could destroy every ongoing development.