An argument can be made for both decades as having a greater impact on the development of US society. Viewing both decades in comparison to US society in 2017, it could be said that the 1920s was more impactful, in the sense that the US in 2017 looks a lot more like 1927 than 1937.
In the 1920s, the country was a war-weary nation that was in the process of turning inward, figuring out its identity following a costly war which didn't directly affect Americans. The result was the election of a questionably qualified Republican president who said that a return to normalcy, to the America of old, was what the nation needed. He pursued heavier tariffs and policies that would withdraw America from the world stage.
The nation was enjoying a soaring stock market setting all time records on a near daily basis. There was a great deal of inequality, and in the absence of a cohesive national vision/identity, people turned to false idols of status, partying, and conspicuous opulence to find meaning and fulfillment. Many illegal drugs, such as marijuana and alcohol at the time, were consumed openly and in large quantities despite their illegality.
Everything written above could be said of the United States in 2017. Let's hope that the parallels do not continue into the 9th year of the decade, when an epic stock market crash led to over a decade of economic disaster in the United States.
