Because a life only based on material possessions is an empty life.
You have to give and receive love from the people around you, for a good morale.
Love is the consolation prize in our messed up world. It's the motivating factor for many people (am I loved, do I deserve love?, how do I find love?, etc.), when they're not driven by fear, that is. Problem is that it's great when it's good, but oh boy, does it suck when it's bad.