The first story took place many years ago as I was walking home from high school with half a dozen friends, fresh off our last day of exams and free for the winter holiday. Passing by a cemetery on the route home, we noticed an empty paper coffee cup lying in the frozen grass in front of a gravestone. We all saw the litter and noted it with regret but kept walking, focused on the celebration ahead. A few steps later, however, we noticed that one member of our group, Justin, had disappeared. We looked back to see him run toward to the graveyard, hop the fence, pick up the coffee cup, and throw it away in the trash can on the street corner.