In fan culture, the term "ship" (short for relationship) has become a verb. To "ship" two characters is to invest your emotional energy into their union. Psychologists argue that this is a form of vicarious attachment. When we watch two characters navigate the "will they/won't they" dance, our brains release dopamine—the same chemical associated with falling in love in real life.
Interpersonal relationships are broadly categorized by the nature of the bond and psychological intent.