Chapter 1 ends with a description of Gatsby's green light. The light is a beacon of his hope in love, a symbol for Daisy. It represents his ideal vision of her: his American Dream. Chapter 2 opens with a description of the Valley of Ashes. Fitzgerald places these two images, the American Dream and the wasteland of failed dreams, together in order to suggest that the American Dream is locked together with the notion of failure. The foreshadowing suggests that Gatsby's dream might end in ashes. The green symbolizes life and money. The ashes symbolize death and failure. Colors play a significant role in this novel. Green stands out as the most suggestive color with conflating meanings of life, money, and illusive dreams.
At the end of Chapter 3, Nick tells Jordan she is a terrible driver. She rationalizes her careless driving by saying that as long as other people are careful, they will get out of her way. Just prior to this exchange, Nick adds that Jordan is completely dishonest. Nick ends the chapter touting his own honesty. Nick places Jordan in the category with the elite, West Egg socialites who are selfishly careless and dishonest. This foreshadows the car accident that will claim Myrtle's life in Chapter 7 and Tom's dishonesty in shifting the blame to Gatsby. Near the end of the final chapter, Nick characterizes Tom and Daisy with the same adjective: careless.
They were careless people, Tom and Daisy—they smashed up things and creatures and then retreated back into their money or their vast carelessness or whatever it was that kept them together, and let other people clean up the mess they had made . . .
Gatsby had been trying to relive the past. In Chapter 5, when Gatsby and Daisy finally reunite, he is actively reliving the past. Symbolically, he leans against a clock and almost knocks it over. Nick adds, "I think we all believed for a moment that it had smashed in pieces on the floor." Playing with time and trying to relive the past are dangerous and/or futile attempts. It foreshadows a potential for this 'reliving of the past' to end tragically. Gatsby even says, "I'm sorry about the clock."