Dead Eyes

Have you ever noticed people in stores when they are alone? It seems like there is usually a deadness in their eyes. I always try to at least acknowledge someone as they go by me, but usually that nod or smile is greeted by a lifeless non-response. Is it that people are just so lonely and empty that they withdraw into their own little worlds and dont' come out for anybody? Is it a defensive measure, not wanting any contact with strangers? Whatever it is, it is another sign of the total breakdown of the idea of family (as in the human family) or community (as in love thy neighbor) and it is truly sad.