Good manners are how you show the people around you that you respect them. Ivan says that safety is a lethal version of manners. I think he has a good point, but they often overlap.
Safety is usually enforced by law, and manners are enforced by social classes. Safety gets more attention (as it should), but I think it's about time we started taking them both a little more seriously. Let this song be a lesson to you. Wash your damn hands and quit driving like an ass.