Gravity

 After walking thousands of miles around the same neighborhoods you begin to realize something. That each neighborhood has its own atmosphere. The air is different and more importantly the gravity is different. While transversing through what most would call a blighted, dangerous urban neighborhood the air seems thicker and the gravity stronger which slows you and begins to drag you down. As an outside this only seems to effect you as the inhabitance of such a place have acclimatized to the hostile environment. In these places you come to the conclusion that time is the worst disease and the leading cause of death is life.