Gatsby and Daisy were in love before Gatsby had to go off to war. During that time, Daisy got married to Tom Buchanan. Upon Gatsby's return, every single decision he has made was somehow related to his grand scheme of winning her back. Since he deems himself not worthy to her he does everything he can possibly do to become an honorable man deserving of her, which meant gaining wealth even by illegal means. Gatsby was so delusional by the thought of Daisy that to perpetuate his impression of her he embellishes it every chance he gets, gracing her with more and more features that came to his mind that didn't before. As time goes on, he perceives her as the object of perfection, when she was clearly not deserving of that title. On page 89, when Gatsby meets Daisy for the first time in years, Fitzgerald writes "There must have been moments even that afternoon when Daisy tumbled short of his dreams not through her own fault but because of the colossal vitality of his illusion No amount of fire or freshness can challenge what a man will store up in his ghostly heart". Daisy was a beautiful, charming, wealthy, and sophisticated woman by first glance. However, she was also an inconsiderate, self-involved, dependent on others person in love with luxury and money.
Consequently, Gatsby's misconceptions of Daisy lead to his demise. His illusion of her made him believe she would be able to love him back when all Daisy really wanted was security. Daisy chooses her husband over Gatsby at the first sign of a conflict arising and runs away leaving others to clean up her mess. This enhances the overall theme in that the past cannot be repeated and the