“The endorphin effect is just one of many biochemical phenomena that explain why people all over the world have traditional folk songs and dances; why children recite the Pledge of Allegiance together in school; why most religions involve congregational singing or chanting as a regular part of services; and why millions around the globe engage in sports. These chemical responses reward us for bringing friends together, secure our sense of belonging, and make social activities good for us, both physically and emotionally.”