Once there was a hungry fox who, while wandering in search of food, came across a vineyard. There, the golden grapes which were very delicious and sweet, hung from the vines.
The fox looked at them greedily and jumped up to have a bite into the grapes, but failed to reach them. He tried again and again with all his capacity, but still could not make it.
Disappointed, the fox then gave up and consoled himself saying, “What a fool I am, trying to eat these grapes! I should have known that these grapes are sour.”
Moral : An unattainable goal looks worthless.