Let's say your office has a coffee maker with 3 pots, 2 regular and one decaf. It's 11:00 and you pour yourself a cup of regular and you finish the pot. At this point what is the proper action? No, don't reach for that switch - turning the burner off and leaving makes you an asshole. If you want to be a responsible member of coffee-drinking society you make a new pot. Yes, even if you're late for a meeting. Maybe you should have thought of that before you decided to empty the pot, you leech.