"The American Dream is being able to succeed based on hard work no matter your religion or your race or the family you are born into. Based on hard work, there are no boundaries to your success" (Abbud).
Gatsby believes that the past does not have to be permanent. He insists that one can erase the past.
Gatsby practically worships Daisy. He only has eyes for her, and, in the end of the story, we see that this only causes problems.