The Great Gatsby is novel that deals with the theme of remaking one's self
. It is about taking your life
and making a radical change
toward what you perceive
. In the end Gatsby is destroyed by himself and the grim spectre of Social Stratification
In the past, the United States was wide open to settlers, and there were limitless possibilities. It is that for which Gatsby yearns. He is trying to regain that past of possibility before his life became stratified. It is the tragedy of our existence that with each passing moment and each decision we make, we kill infinite future possibility. Each thing we do, and each thing that happens to us becomes a part of our definition. And a definition is exactly that: a limit. Every second we are more and more limited. And since America had progressed without him while Gatsby was away during the war, he was thrown back into his life wishing for the past. The sad fact was that he could never regain that past, he could never regain what he wanted. In vain he attempts to reinvent himself, and open up his life by destroying and hiding his past.
But simply destroying who you are cannot affect the world outside of you. And so he fails in his quest to regain the past life, because society exists as a limit to who he can be, and his past still exists as a limit to who he can be. He couldn't destroy his past desire for Daisy, and so he could never truly be happy, because he was never truly reinvented, his past still haunted him.