This chapter describes extensive empirical evidence documenting the surprising cognitive and behavioural benefits of mild negative moods. Advocating the acceptance rather than the elimination of negative affect might at first sight appear counterintuitive. Much of clinical and counselling psychology is devoted to managing negative affectivity and alleviating sadness. Evolutionary psychologists, puzzled by the ubiquity of dysphoria, have speculated that negative affect may provide hidden social benefits by possibly arousing interpersonal sympathy and reducing the likelihood of interpersonal challenges and competition. Democritus and the Cyrenaic school developed a hedonistic philosophy suggesting seeking the good life involves exercising wise judgment to obtain pleasures through love, friendship, altruism and justice. Negative affective states that are intense, enduring and debilitating such as depression clearly have very negative consequences and require clinical intervention. Many of the classic works of Western culture and civilization in particular also deal with the evocation, rehearsal and even cultivation of negative feelings and emotions.