Gatsby is a man who is able to rise above his very humble beginnings, leaving his past behind to recreate himself. He is smart and willing to work hard and take risks to get what he wants. It seems that he has been successful until he falls for Daisy. His inability to let Daisy "go" when they meet the second time in his life is Gatsby's undoing. "Great" is a relative term. In some ways I think he is great in becoming someone much different than he would have been had he not had the dreams and desires to grow and be successful. However, like a tragic hero, he has a flaw that keeps him from greatness or true success. His ill-conceived love controls him and obsesses him. It is here, then, where he loses sight of all he wanted to be (though we may question the methods and means he used to get there), and then loses everything else that might have mattered to him. He loses himself, and this is truly tragic.