One of history's fews iron laws is that luxuries tend to become necessities and to spawn new obligations. Once people get used to a certain luxury, they take it for granted. Then they begin to count on it. Finally, they reach a point where they can't live without it. Over the few decades, we have invented countless time saving machines that are supposed to make like more relaxed - washing machines, vacuum cleaners, dishwashers, telephones, mobile phones, computers, email. We thought we were saving time; instead we revved up the treadmill of life to ten times its former speed and made our days more anxious and agitated.