A Stranger Walks Into Ma Pa Store

A stranger walks into a Ma Pa store and spots a sign:
“Danger! Beware of the Dog”
Just as he got inside, he sees a harmless old hound, fast asleep in the middle of the floor.
“Is that the dog we’re supposed to beware of?” He asks the owner.
“That’s him.”
The owner replied.
“He doesn’t look dangerous to me. Why would you post that sign?”
“Before I posted that sign, people kept tripping over him!”