The Donkey that Thought it was Clever

Once upon a time . . . a donkey thought he was very clever. Every day, his
master harnessed him to a cart loaded with goods. They always went the same
way to the village: along a wide path through the wood, down a gentle slope
into farmland, then along the river to the ford and over the plain to the
village.
Since the route was always the same, the donkey's master had got into the
habit of having a snooze on top of the cart while the donkey, who knew the way
by heart plodded on.
Feeling unwell one day, the man decided to risk sending the donkey by
himself with a load for urgent delivery. When the animal returned, he was
given a double ration of oats as reward.
"Since you're so clever at remembering the way," the man said, "I'm going
to send you alone always, then I can do other jobs!" And from then on, in all
kinds of weather, the donkey travelled to the village by himself. His master
was delighted.
However, one morning, when the donkey reached the river, he decided to
shorten his journey by wading across the water. But he entered the river at a
deep spot, much deeper than the donkey expected, and he had to swim against
the current.
Luckily, he was carrying a load of salt that day, and some of it
dissolved in the water, easing the donkey's load, so that he reached
the other side without much difficulty. "I am clever," said the donkey,
pleased with himself. "I've found a short cut."
Next day, the man loaded the cart with sponges, and the donkey set off as
usual. When he arrived at the river, he again thought he would take the short
cut, and entered the water as he had done the day before. But this time, the
sponges soaked up the water and made the cart heavy, so that the poor animal
could not keep his head above water. And in spite of all his efforts, the
donkey that thought he was so clever, sank below the surface of the water
together with his load.