Why would you have to tell grown people to...

Why in the world should anyone have to tell grown ass people to cover their mouths when they cough/sneeze and to wash their hands?! Now that the swine flu is "running rampant" we have to remind people to do what they should be doing eveyday whether something is going around or not. I just don't get it...maybe I'm crazy, but I cover my mouth and wash my hands.