Whenever you lose a pet or want to sell furniture, the most simplistic and old-school way to get your message across is to hang up a flyer on a street post. It's easy to do because all you need is paper and a few staples to make people aware of your cause. However, hilarious pranksters from around the world have adopted this practice and taken it to a new level by posting joke signs. These signs aren't meant to advertise anything. They are there just to make you smile.