I think it is a uniquely American trait that permits us to ignore the span of thousands of years of history and monetary lessons taught to us by countries far greater, wealthier, stronger and wiser.
Very true. Americans are the forever positive types. Talk to an unemployed European mid-level manager and he'll complain about his lot. Talk to the same unemployed American and he'll tell you how blessed he is and that being jobless is a blessing that will lead to better opportunities.
Every American thinks that he'll eventually make it into the ranks of the rich (although the stats point otherwise). Therefore he doesn't really mind the privileges of the rich; and he's willing to work hard and kiss ass for the opportunity.
I know it's a gross generalization. But the positive American attitude does contribute to a more dynamic economy.