A man took his Rottweiler to the vet and said, "My dog's cross-eyed. Is there anything you can do for him?"
"Well," said the vet, "let's have a look at him."
He picked the dog up and examined its eyes carefully.
"Well," said the vet, "I'm going to have to put him down."
"Just because he's cross-eyed?" the man asked, shocked.
"No," replied the vet, "because he's heavy."