The Shepherd’s Boy and the Wolf
There lived a shepherd boy in a small mountain village. He had great imagination, so one day, an idea occured to him to have some fun and escape from the monotony of his life. So he went very close to the village so that people could hear him and began to yell: "Wolf ! Wolf! Help me!”
The villagers got scared and wanted to help him, so they came quickly, but instead of wolf, they only found the shepherd boy laughing ironically.
“Foolish boy!”, they said very angry and left.
The boy was really proud of himself and did his stupid joke once again another day and the villagers believed his lie again and felt sorry they fell into his trap.
The third time the shepherd boy cried for help, nobody bothered to help him any more and this time the wolf was real, it was not a joke, but the villagers didn’t believe him any more.
Once you lose your credibility, no one will believe you any more, even when you speak the truth.