Thanks for the responses, folks!
Farkel... so are you saying that you believe that the psychological difference was because WWII was a just war?
Realist... WWII seems to me to have been more a matter of political than of economic competition. How do you figure that economics was at the base of it?
Anyway, whatever caused the war, I think it's clear that it was necessary as a defense of democracy. Hitler was killing millions of innocent people, and he had plans for taking over all of Europe. He had to be stopped.
Blondie... interesting; I hadn't thought of the effect of the Spanish flu.
Talesin... I was thinking of googling, but I wasn't sure what keywords to use. I'll try those, thanks!
The thing is, WWI did lead to a period of prosperity also. Not in Europe, necessarily, but in the United States. It was also a period of social dislocation, however, whereas the post-WWII economic boom was a period of social stability. So I think that's the main difference I'm wondering about.
Flash... If people adopted to the new era, then why did Vietnam produce so many broken soldiers, just like WWI?