A nice afternoon ride?

So it's a warm, slow day on the ranch, and the rancher tells his wife that he's taking her on a horse & buggy ride through the countryside. Before long, they come to some railroad tracks and the horse stops. Nothing will get the horse moving, so the rancher gets out of the buggy, takes the horse's bridle and leads him across the tracks. Pointing his finger in the horse's face, the rancher says, "That's once!" And he gets back in the buggy, and they're rolling along again.

Pretty soon, they come to a highway and the horse stops, won't move. Nothing the rancher does will get the horse to go, so again he gets out of the buggy and takes the horse by the bridle to lead him across the highway. He points his finger in the horse's face and says, "That's twice!" Then he gets back in the buggy and they're going again.

After awhile, they come to a bridge and the horse stops. The rancher can't get the horse to go. So he gets out of the buggy, points his finger in the horse's face and says, "That's three times!" Then he pulls out his revolver and shoots the horse dead.

As the horse collapses to the ground, the rancher's wife starts screaming at him. "What did you just do? You just shot our horse! I can't believe you did that! How are we supposed to get home? What kind of maniac are you? I can't believe you shot our horse...!"

And the rancher points his finger at her and says, "That's once...!"