In the 18th century, the Enlightenment ushered in the notion that happiness was the attainment of a worthy life. Since then the pursuit of happiness has spread to every aspect of behavior, from religion and politics to work and parenting. Today the happiness imperative creates pressures that, paradoxically, can make us miserable. Sadness is often mistaken for a pathology. Understanding the cultural commitment to good cheer as an artifact of modern history, not as an inherent feature of the human condition, opens new opportunities for understanding key facets of our social and personal experience.