According to the Great Gatsby, what traits constitute the zeitgeist (spirit of the time) of the 1920s?

Symbolized by the Valley of Ashes in Chapter Two of The Great Gatsby, the Jazz Age of the 1920s was a period of moral and spiritual corruption, materialism, and superficiality. With Daisy's voice that "sounded like money" and the amoral quality to Jordan Baker who depicts the typical "flapper" flitting from party to party, enjoying the "intimacy" of large parties such as those on the lawn of Gatsby, and who thinks nothing of cheating in golf tournaments, lying to people, or gossiping, the "grey names" and the tenor of the times are aptly depicted. In fact, Gatsby's parties where his guests "paid him the subtle tribute of knowing nothing whatever about him" present a tableau of the vulgarity and spiritual emptiness and even a cynicism as, for instance, Nick's remark in Chapter Six about looking at the world through Daisy's eyes conveys,

It is invariably saddening to look through new eyes at things upon which you have expended your own powers of adjustment.

Also symbolic of the Roaring Twenties is the frequent allusion to gold in reference to Daisy. Like her, the gold is only superficial, a gilding over the tarnished surface. About Fitzgerald's setting, one critic observes,

America has become vulgar and empty as a result of subjecting its sprawling vitality to the greedy pursuit of money.

In such a decadent society, there is a lack of moral structure in the setting of The Great Gatsby where much of what exists is merely an illusion.