What was the most important effect of WWII on American cultural life?

World War II had many major impacts on American culture.  The most drastic impact was that it helped foster a spirit of unity and patriotism.  

The United States entered World War II in December of 1941.  The war had already been raging on for over two years at this point.  Political leaders, such as President Franklin D. Roosevelt, encouraged Americans to unify together for one common goal: winning the war and defeating the Axis powers.  Propaganda, such as pamphlets and posters, implored Americans to sacrifice to help support the troops overseas.  Even many American films in the early 1940s featured noble women who worked hard while their men were overseas and heroic men who served as soldiers.  Thousands of young men voluntarily enlisted in the military.  Americans were encouraged to collect scrap metal, eat less of certain foods, and reuse what they had in order to support the war effort.  Patriotism increased during this time.