The title of the novel The Great Gatsby indicates the dual nature of Jay Gatsby's characteristics. The name "The Great ______" calls to mind an illusionist, whose sole purpose is keep the audience from seeing what is really happening. In fact, Gatsby's two names—James Gatz and Jay Gatsby—also indicate this duality.
Gatsby's positive qualities can be summed up by Nick in Chapter 1:
"[I]t was an extraordinary gift for hope, a romantic readiness such as I have not found in another person and which it is not likely I sha ever find again."
I generally credit that "gift for hope" to James Gatz, the boy who made something out of himself when he had nothing.
Many of the positive traits Gatsby possesses can be traced to the days in which he was named James Gatz. When his father shows up near the end of the novel, he shows Nick the routine Gatz set for himself when he was just a boy. This singular mindset is what led Jay to be successful (even if he gained his riches through illegal activities).
However, while the reader likes to focus on the romantic aspects of the book, Jay Gatsby (not James Gatz) has some awful characteristics. Start with the obvious: Jay Gatsby attempts to destroy a family in order to "recover some part of himself." Sure, that family is probably not a happy one, but it doesn't make his actions okay. Throughout the affair, there is no mention of Daisy's daughter either.
But here are two other, less obvious, negative characteristics:
- Gatsby uses Nick in order to get close to Daisy. That's the purpose for the car trip to the city and lunch.
- Gatsby's choice of Wolfsheim as a character reference is an obvious poor choice. He's violent and runs a criminal organization. This decision indicates a lack of a realistic world view.
One final note, when reading Gatsby it is always important to remember that the narrator is completely unreliable. At the most basic level, he's good friends with Gatsby. At a deeper level, the reader can assume that Nick might, in fact, be in love with Jay. This might be why readers have a difficult time noticing Gatsby's negative characteristics.