Gatsby is seen as "Great" because of his ability to dream and be driven to live because of his dreams. I think that part of the allure that Gatsby has is that he represents the irrepressible spirit of identity and freedom that are so intrinsic to America. This is not a culture whereby individuals are born into a lot in life and cannot escape it. Gastby redefines his own identity and does so in such an intensely extravagant manner that one could only see him as "Great." For a world that lacks dreamers and those who are inspired by it, Gatsby is an individual who really sees things differently and uses them as a source of motivation to make what is into what should be. I think that this is where he emerges as "Great." The other implication of "Great" can also refer to size and magnitude. Gatsby dreams big, creates wealth that is opulent in his display, and constructs reality that is larger than reality. In this, Gatsby represents another typical American idea of obsession with size and abundance. The demonstration of his wealth is part of his dream in winning Daisy. In the end, these reflections are what makes Gatsby "Great."