In the spring, Nick Carroway feels comfortable in his new home and is trying to assimilate in witht he wealthy residents of East Egg.
In the summer, Nick begins to attend Gatsby's wild parties and begins to become closer friends with Gatsby. With this, Nick has to get in the middle of Gatsby and Daisy's affair which creates emotional turmoil for him.
After the heat of the summer, Nick cycles back to his pessimistic self; as he was before the summer and his move to East Egg. He now once again resents weatlh, after realizing all of the problems it created within the lives of Gatsby, Daisy and Tom.