Say you're walking on the footpath in a haste. But the guy walking in front of you is slow and is blocking the entire path, so you can't even bypass him. That's annoying, isn't it? Similarly, you should be careful about your walking speed, for others behind you may be getting irritated. Don't walk too slowly. If you need to walk slow for some reason, stick to the left and allow sufficient room for others to pass. Remember, the street isn't made exclusively for you.