Mules are strong animals.  They haul heavier loads and travel trickier roads than horses.  They climb mountains with surer feet.  Mules can travel longer without water and food--positively wonderful animals.  However, mules are proud of being mules and they are also stubborn.  They know their worth and they expect compensation for their hard work and loyalty.  If more is demanded of them than they consider proper they may exercise their "mule rights" by refusing to budge another step.  Furthermore, if after they protest and the negotiations go against their dignity or their sense of  total contract obligations they express their displeasure a in most emphatic manner. 

      To illustrate this point: one day on a very large ranch, one that hired many cowboys,  some of the older hands--namely, one of the mule teams--decided they were not receiving the attention that was their right. After waiting for things to change for what seemed to them a period of time,  they realized that their waiting was in vain.  Therefore, they, just as humans do, decided to demand it.

      So, the next time they were hitched to a huge wagon they refused to pull the load of dry straw, cans of oil, and other flammables.  The cowboy turned muleskinner,  yelled and swore his orders.  Not even an ear wiggled.  He yelled louder and swore more fervently.  Not an eyelid blinked.  He cracked his whip.  Not a tail swished.  He got down from the wagon and pulled at the heads of the team.  He wasn't strong enough to cause either mules to take a step.

      He, the muleskinner, decided to give them one more chance, so he went through the entire routine.  He yelled his tirade that the mules usually loved and usually responded to with movement.  Not a motion.  He swore--now in anger.  No response.  He lashed at them with the whip.  They never quivered.  It seemed to be a complete stand-off. 

              This determined Muleskinner was not to be outdone by a team of dumb mules.  He was furious!  He had reached his limit. He decided he'd  show that he was the boss, so he decided on extreme measures. He took some of the dry hay, some of the oil, a few matches and he built a fire under the mules.

            The equally determined, here we can substitute the word stubborn, mules waited just long enough for the fire to have a good blaze going before they moved.  When ready the crafty mules moved straight ahead.  The muleskinner jumped on the wagon, sure he had won.  He yelled in triumph and tossed his hat.  At that exact moment the mules stopped.  The brightly  burning fire was exactly under the middle of the wagon carrying the flammable items.  The wagon's contents exploded and tossed the jeering muleskinner through the air after his flying hat. 

            What a joyful noise those mules made as they brayed and brayed.