Husband Wife Mule

'Once there was husband and wife who had just bought a new mule.
They were walking it down the street when the mule trips over a stone.
The husband says, "That's one!"
They walk some more, when the mule trips over a stone again and the
husband says, "That's two!"
Then the mule trips over a stone again. The husband says, "That's
three," and shoots the donkey!
The wife gets so mad and start's cursing at the husband and saying,
"That was are only donkey! You were an idiot to shoot it!"
The husband says to his wife, that's ONE!"