Final answer:
Gatsby grew up in North Dakota, which contradicts his claims of elite origins. Fitzgerald's 1920s were marked by success and regret, emblematic of the decade's allure and underlying discontent.
Step-by-step explanation:
Jay Gatsby, the titular character of F. Scott Fitzgerald's novel The Great Gatsby, grew up in the Midwest, specifically in North Dakota. This is contradictory to what he tells others about himself, namely that he comes from wealth and a privileged background. Gatsby's deceit reflects the novel's themes of illusion versus reality and the American Dream's corruptibility.
Fitzgerald, in his essay "The Crack-Up", describes the 1920s through his experience as a time of disillusionment. While successful as an author, his twenties were marked with regrets, such as not playing football in college or serving overseas during World War I. Fitzgerald portrayed the decade as having surface glamour but also a deeper sense of restlessness and dissatisfaction, a reflection of the broader societal experience of the 1920s.