There was once a young shepherd boy who repeatedly lied the other to amuse himself. One day he wanted to have fun so he called out "Wolf Wolf, help me!" The villagers came out to help him, but was no wolf, The boy laughed at them happily.
But stortly after this, the wolf truly appeared and attacked his sheep. The shepherd boy cried out of help louder than before, but this time nobody came to help him. And finally, the wolf ate up his and then slipped away in the forest.
Moral of the story : A liar's truth is seldom believed.