One. You don't believe me do you? I've got photos! See that big blob? Well, just squint your eyes a bit. . . .
or
A mushroom!
or
Two. One to assure the everything possible is being done while the other screws the bulb into the water faucet.
or
It needed a root canal.
or
The bartender offers him a warm smile and says, "For you, no charge".
or