The blind man was out walking with his Guide dog when suddenly the animal paused and wet the man's leg. Bending down, the blind man stretched out his hand and patted the dog's head.
Having watched what happened, a passerby said, "Excuse me, why are you patting him? That dog just pissed on your leg!"
"I know," said the blind man, "but I've got to find his head before I can kick his arse."