A fireman is polishing a fire engine outside the fire station when he notices a little girl next door in a little red cart with little ladders hung off the side and a garden hose tightly coiled in the middle.
The little girl is wearing a fireman's helmet and has the cart tied to a dog and cat.
The fire fighter walks over to take a closer look, "That's a lovely fire engine," says the fireman admiringly. "Thanks," says the little girl.
The fireman looks closer and notices the little girl has tied one of the cart's strings to the dog's collar and one to the cat's testicles.
"Little girl," says the fireman, "I don't want to tell you how to run your fire engine, but if you were to tie that rope around the cat's collar, I think you could probably go a lot faster.
The little girl pauses for a moment to think, looks at the wagon, at the dog and at the cat, then shyly looks up into the fireman's eyes and says...
"You're probably right, but then I wouldn't have a f**king siren, would I".