The crowd erupted with energy as Michael Phelps began to close in on the Serbian star, Milorad Cavic, in the Beijing Aquatic Center. As the Olympians neared the wall, the tension in the aquatic center...

Suppose that a student drops a pen on the ground while in class. His teacher, a person who obsesses over cleanliness, berates him. She tells him how careless his pen-dropping habits are. The kid is nearly...