A blind man stood at a street corner with his guide dog, waiting to cross. Suddenly, the dog lifted its leg and urinated on the man's fine herringbone tweed trousers. The man promptly took a dog biscuit from his pocket and offered it to the dog.
A businessman observed this from across the street. "Excuse me, sir," he called out, "did you know your dog just urinated all over your pants?"
"Yes," replied the blind man. "It's a dreadful habit I'm trying to break him of."
"Well, it's none of my business," said the onlooker, "but you won't teach him much by rewarding him with a biscuit!"
The blind man chuckled and said, "I'm not rewarding him. I'm just trying to find his head so I can kick his behind!"