As good people, we taught our kids that littering isn't nice. As humans, we also let some curse words fly in front of them.
We were at our city's 4th of July celebration when the oldest was 4. We were walking around and someone tossed their trash on the ground. Captain Litterbug flew into action, picked up the trash and yelled, "Hey a**hole, you dropped this," while tapping them on the butt.