"The object relations theory suggests that during the formation of early relationships, the infant psyche identifies part objects by the function they serve. For example, a breast that produces milk is seen as a good breast. A hand that touches and caresses is seen as a good hand. But a mouth that yells and hurts is seen as a bad mouth. These object identities develop through years of receiving care and the events that occur during that time. Although these representations are skewed and do not accurately depict the tangible object, they eventually grow to represent them. This causes extreme ambivalence within a client who has seen good and bad parts of the same person." - Object Relations

Found this, it has an example... I like examples