Like all feeling states, happiness is an evolutionary adaptation, responding to the biological imperative to survive and reproduce. Unlike some feelings, it is complex, comprising a balanced combination of elements from each of the three mental structures initially hypothesized by Freud in 1923 and supported in recent years by neuroscientific research. A particular challenge to happiness posed by modern society is the problem of addiction. Addictions in the id, ego, and superego are defined, and therapeutic approaches to these and other obstacles to happiness are described.