Adults live in a variety of relationships that differ in the individual form created by the people involved – for example, the relationship might be intense, superficial, full of conflicts, or boring – as well as in the basic type. These types include relationships with parents and children, love relationships, marital relationships, friendships and acquaintances, relationships with colleagues at work and with neighbors, relationships with people who share similar interests or convictions (members of a film club or a church community), and relationships with patients, clients, and superiors. All these relationships can be fulfilled to varying degrees of satisfactions: people can be bad or good fathers, lovers, or colleagues; they can also violate general conceptions of the relationship to such an extent that those affected, or observers, are of the opinion that someone who behaves in this way is not a father, a friend, or a colleague. Often people are very definite in this kind of judgment, although there is usually no written code of conduct for a particular type of relationship.

Although people often learn about a particular type of relationship only when they enter one in the course of life, the idea is widespread that fundamental skills in initiating and maintaining a relationship are already developed during childhood. According to attachment theory, these skills are rooted in the secure attachment built up in the first year of life between the child and the person caring for it (Ainsworth, Bell & Stayton, 1974; Bowlby, 1969).