Stubborn as a mule?

I have often heard the phrase, “stubborn as a mule”. Yet here are 20 mules pulling some heavy load through a desert. It’s not like the driver is able to do anything to force them to do so, the mules in front are out of reach and probably can’t even hear him. They are too busy watching for rattlesnakes, anyway.

The mules of that era would be ashamed of today’s mules; those punks balk at even easy jobs, like hauling tourists through a scenic canyon. Maybe mules just don’t like people on their backs?

The original painting depicted here now hangs in the Dow Hotel in Lone Pine, California