A duck had a $100 bet with his friend

A duck had a $100 bet with his friend that he could touch the tip of his beak with the end of his foot. Certain that ducks aren’t built to do this kind of thing his friend takes the bet. After several attempts, rolling around on the floor, flapping around and making a fool of himself, the duck fails miserably at the bet. He gives his friend a sideways glance and admits that he can’t pay up. His friend, understandably disappointed but unsurprised says “that’s ok, I just hope you didn’t injure yourself during process” What’s the moral of this story? Only take a bet with a friend if they can foot the bill.