Your phone buzzes in the evening: “You are 3,000 steps away from your goal.” So you pace around the room, walk up and down the corridor, or take one more round of the lane before bed, just to hit the magic number.
Millions of people do this every day. But have you ever asked why the goal is 10,000 and not 8,000 or 12,000? The answer is more surprising than most people expect.
