The Grant Depression led Americans to believe that President Herbert Hoover was to blame. Hoover entered office, right as the stock markets crashed, and he could not do anything to prevent that. America learned that they could persevere through thick and thin as a country. That not even a money drought can stop the United States of America.
Yes... The Germans were doing many bad things at the time and they were also invading a lot of countries in the beginning in of the war (before the US entered). With America’s intervention, the German military was overwhelmed by manpower and materials coming from the US to aid the Allies
It created tensions between the two sides and pushed towards towards the start of the American Revolution