More stores are requiring workers to show up on Thanksgiving Day, and Americans already work longer and harder than anyone else in the industrialized world. In the only advanced economy with no guaranteed paid vacations -- and when they are available, workers don't take all the days they're entitled to. The 40-hour week is a thing of the past, not only because of economic necessity. Even the rich are working harder than ever, despite evidence that overwork reduces productivity and makes for illness of both the mind and the body. Do we do it by choice, or is it part of the culture? Will technology make us free?