A couple was celebrating their golden wedding anniversary. Their domestic tranquility had long been the talk of the town. A local newspaper reporter was inquiring as to the secret of their long and happy marriage. Well, it dates back to our honeymoon," Explained the man. We visited the Grand Canyon and took a trip down the bottom of the canyon by pack mule. We hadn't gone too far when my wife's mule stumbled. My wife quietly said, "That's once." We proceeded a little farther when the mule stumbled again. One more my wife quietly said, "That's twice." We hadn't gone a half mile when the mule stumbled a third time. My wife promptly removed a revolver from her pocket and shot him. I started to protest over her treatment of the mule when she looked at me and quietly said, "That's once."