In the 1920s americans were celebrating, what were they celebrating?

The number one thing was the ending of Wold War I. The war was immensely destructive, taking over 38 million lives. Once the war had ended in 1919 with America and the Allied Powers victorious, there was of course reason to celebrate. After this, economic trading was drastically increasing, there was a legendarily massive stock market boom, and all of society seemed to be heavily prospering.