Rooby: If the car breaks when you are driving it, who should you call?
Me: You should probably call a tow truck.
Rooby: And what would they do?
Me: They would tow the car to a mechanic, and hopefully the mechanic would fix it.
Rooby: And then what?
Me: Then you would drive it home.
Rooby: Or to a store.
Me: Right. Or maybe to a restaurant, if you were hungry.
Rooby: And if all of your teeth fell out, then who should you call?
Me: I guess in that case you should call the dentist.
Rooby: No. You should call the Tooth Fairy.