Imagine a child. They are angry at their mother because she didn't buy a toy. But the family rule says: "You cannot be angry at mom, that's bad." If the child shows anger, they risk losing love (the basic need for safety). What does the psyche do? It finds a workaround. The child learns: if I pout, go to the corner, and cry quietly (demonstrating resentment), mom will feel guilty and come to comfort me. Bingo! The child got what they wanted (attention, strokes), but at the cost of giving up their power (anger) in favor of manipulation (resentment).