Sisyphus wonders why positive feedback from colleagues, teachers, etc. is not as satisfactory as that from parents. In other words, for someone deprived of, for example, sufficient affirmative (selfobject)experiences >from their parents, the substitution of affirmative experiences from colleagues, friends, teachers, others, etc. will not fill the deficit enough to relieve the residual need, and, therefore will not significantly relieve the symptoms derived from this residual need or from the defenses against it.
The above is true generally for all individuals. No one can really shake off the craving for receiving the needed responses specifically from parents or from the equivalent early significant caregivers. The reasons for this is to be found in the inescapable overvaluation of the parents by the infant since they are the ones who spend most time with the child, the ones who seem all powerful in that they can do all the things that the infant cannot do, including relieving the discomfort of hunger. The gap between the infant's experience of his/her relative helplessness and the caregiver's apparent omnipotence is never greater than in infancy and is never totally forgotten. No one will ever seem quite as powerful and beautiful and respected by the infant as the early caregiver. This experience leads to expectations that this idealized other will keep providing all this wonderful care. Of course, this expectation is bound to be disappointed in time. As far as future mental health is concerned everything depends on how this disappointment occurs. If the disappointment is slow and gradual in coming and occurs within a context of loving affection then the child learns to do more and more for his/her self and gradually expect less and less from the caregiver except the continuing experience of being loved. If however the child's disappointment is more than can be easily mastered by the young and fragile self (e.g., too sudden, too fast, too severe, too painful, administered without the needed warmth and affection appropriate for the age and development of the child) then the child cannot cope by learning and doing for self and the need for the earlier selfobject experience remains. Such a need may be expressed in demands on the parent who may react negatively so that the child is forced to suppress/repress it out of conscious awareness and the child's behavior may no longer reveal the presence of the unsatisfied need to the untrained observer. Other defenses may also come to be adopted. The point is that unconsciously the need persists and craves for satisfaction even into adulthood. And unconsciously the hope for finally getting some satisfaction is never given up so that child-like demands (and, perhaps, the defenses against this) keep cropping up throughout life.
In later life the friends, colleagues, etc. may try to satisfy the needs as they manifest but they cannot because these later potential selfobjects are not experienced with the same degree of idealization as the parents once were. They may try but the unconscious memories of the childhood bliss can only rarely be equaled. However, there are some exceptions to this. Certain religious, artistic and love experiences can become intense and effectively substitute for the missing childhood experiences. And, of course, in psychotherapy, if conducted empathically and with enough frequency and intensity, the repressed early expectations are revived and become expectations addressed to the therapist (transference). Inevitably these will be disappointed and the resulting disruptions in the therapeutic relationship become either failed therapy, or, if managed competently, can become instances of repair of the relationship and therefore moments of renewed growth of the self and of healing. But, please note, it is not the satisfaction of an adult's infantile needs that is therapeutic but the repair of disrupted relationships with the therapist.