People require affection for the complete development of their nervous system. But sometimes the caregivers can't provide sufficient levels for said healthy development, often leaving a permanent scar in these younglings, a developmental trauma. Such a person won't have a sufficiently developed internal sense of self-worth, self-love and will require more external supply of validation, affection. Succeeding in various endeavors becomes a "life-and-death" issue, because at it's core it's a reflection of the imperious need of a mammal for nurturing by their parents.

Often, siblings become competitive with each other for precisely this reason. They are competing for the little affection their caregiver provides.