The Fox and The Grapes
A hungry fox saw bunches of ripe grapes hanging from a vine. His mouth watered. He became happy thinking that these juicy grapes would satisfy his hunger. But the grapes were too high. He jumped and jumped with his mouth raised but failed to catch the bunch. Every time he used to fall down with a thud. Constant jumping tired him. To regain breath he sat down and jumped again but got no success. Finding no way to reach the grapes he went his way all disappointed and defeated. To console himself he said that the grapes must be sour and that was the reason why he failed to get them. These words he uttered simply to cover his own inability. He was not ready to accept his weakness.
Moral: Do not curse others for your shortcomings.