Although most people like to be alone at times, most also choose to spend the majority of their time involved in relationships with other people. So important are relationships that, when asked about the factors that give their life meaning, participants in one study rated most highly their interpersonal relationships with others (Klinger, 1977). The nature of these relationships can take a number of different forms, including casual acquaintances, friendships, family relationships, working relationships, and romantic relationships. The duration of these relationships may be short-term or long-term. People's intense desire to affiliate and form relationships with others stems from an innate need to belong (Baumeister & Leary, 1995). Much of people's behavior is driven by their desire to be included by others and to avoid being excluded by them. As anyone who has ever been ostracized or excluded can attest, the consequences of being excluded from important interpersonal relationships can be severe and include both psychological and physical problems.