Once there was a shepherd boy who looked after his sheep on a mountain near a forest. The boy thought it was a boring job, and except for three farmers he could see in the distance, he was alone.
One day the boy thought of a plan to get some company. He started to shout ‘Wolf! Wolf!’
The farmers came running, but found no wolf. One of the farmers, however, stayed and talked to the boy for a while.
Having company was more fun than being lonely and so, a few days later, he thought he would do the same thing.
‘Wolf! Wolf!’ he shouted.
Again the farmers came running, but again they saw no wolf.
A few days after that, a wolf did come out of the forest. It started to attack the sheep.
‘Wolf! Wolf!’ the boy shouted.
The farmers, however, had become tired of the boy tricking them, and this time they did not come running. The boy, alone, could not stop the wolf as it ate his sheep.

Moral: Those who lie often are not believed, even if telling the truth.