A farmer has to go out to plow his rental field about 10 miles from his farm. To get there he must drive his tractor, and his dog old Joe trots along beside him. Halfway through the plowing, the tractor runs out of fuel.
He wanders out to the road and flags down a ride, which just happens to be a Ferrari. The driver says,
"You can have a ride, but that dog can't get in my car."
The farmer says,
"Don't worry. Old Joe will keep up."
The driver figures he'll show the farmer just what his car can do and lets it rip. Just as he is going into 5th gear, he looks out the window and sure enough Old Joe is right beside him. He can't wait to have a look at the amazing dog, so he slams on the brakes, and the car stops rather abruptly.
The driver jumps out of exclaiming,
"He's the most incredible dog I've ever seen! But what kind of collar is that he's wearing?"
The farmer shook his head and said,
"That's not a collar. That's his ***hole. He's not used to stopping that fast."