Farmer sold a surplus mule to his neighbor, extolling the virtues of this hard-working beast. Said he'd pull anything with all his might.
So the neighbor took the mule home, hitched it up and was pretty ticked off when the stubborn mule wouldn't even lean into the harness.
Headed back to the neighbor that sold him the mule and complained what a bad deal he'd made - that mule won't pull a thing!
The former owner headed right over to the neighbor's farm where the mule stood hitched up in the exact same spot where the new owner had left him.
Picking up a loose fence rail, he gave the mule a crack over the head that laid him right to his knees, then hollered "GIDDAP!"! The mule got back up, shook his head and leaned into the harness with all his might.
The new owner was amazed and said how'd ya git 'im to listen?
The first owner said, oh, he'll listen all right, but first you gotta get his attention!