Sublime K9

This was once recognized as the world's best joke.

A dog walks into a telegraph office to send a message.
The telegraph operator says, 'OK, go ahead.'
The dog says,
'Woof, Woof, Woof,
Woof, Woof, Woof,
Woof, Woof, Woof.'
The telegraph operator says, 'You know we have a special today, buy nine words get the tenth word for free. Would you like me to add another 'Woof'?'
The dog replied, 'But then it wouldn't make any sense!'