Saying ‘yes’ is one of the dominant tropes of American life. America’s favorite politicians are the sunny optimists: think Ronald Reagan and "Morning in America." In fact, the culture is so insistent on looking on the bright side that, as Barbara Ehrenreich complained in a recent book, injunction can be heard on the cancer ward. You might even say -- and some historians have -- that Americans themselves have been pre-selected for their optimism: you or your ancestors had to have a powerful faith in the New World and the opportunities here to make the trek over in the first place.