Space Cushion

So in driver's ed they tell you that you should always have a "space cushion" between you and the cars in front of, behind, and next to you. This means that there should be a certain number of feet between you and these other cars. I think this should apply to walking as well. There is never any valid reason why you can't have 6 inches between you and the people around you. Do us all a favor and respect personal bubbles.