One conversation (toward the end of Chapter 5), shows Gatsby''s infatuation for the Daisy as well as his perception that he will never attain her. "If it wasn't for the mist we could see your home across the bay," said Gatsby. "You always have a green light that burns all night at the end of the dock."
The mist equates Daisy with something that is intangible. The green light ("Go") is an important image that occurs repeatedly, simultaneously attracting Gatsby and pushing him away.
In a more general way, you might think about how often Gatsby calls the narrator and all other men "old sport." It is his rather tired attempt at affectation. Most people remain dazzled by Jay Gatsby's wealth and power and this appellation fits right into their image of the man.