Friendship is a relationship between two people who care about each other. Friendships exist on a continuum from casual acquaintances to close relationships. The study of friendship spans multiple academic fields including sociology, psychology, anthropology, philosophy, and zoology. Various theories have been proposed to explain friendship, such as social exchange theory and equity theory. The value of friendship comes from a friend who consistently demonstrates caring about the other's well-being, empathy, honesty even when difficult, mutual understanding, enjoying each other's company, trust, and an equal give-and-take relationship where one can be themselves without fear of judgment.