Industrialization, urbanization (first time in U.S.
history that more Americans lived in cities than
on farms), jazz (+Harlem Renaissance),
Prohibition, flappers/women earning the right to
vote/huge increase of women in the workforce,
LEISURE TIME (sports, film, etc), cult of the
individual hero (i.e. Babe Ruth, Charles
Lindbergh, Jim Thorpe). There's a ton you could
talk about. But the end of World War One and
the urbanization that resulted from it (also
caused by the "American Dream"), along with
industrialization are probably the most
important, and seem to have set the scene for
everything else.