Once a wolf killed a lamb and started eating it. Suddenly a piece of bone stuck in its throat. It cried out of pain and called for help. There came a crane. The wolf lured the crane so that it would give a lot of rewards.

The greedy crane immediately agreed and removed the piece of bone with its long nose. The wolf was relieved of its pain. Then the crane asked for the rewards.

The wolf laughed at the crane and said, "I have already rewarded you without biting your head. Run away from here, else I will kill you". The crane was very much disappointed and ran away to save its life.

Moral of the story: You should help only those who deserve it.