The fox looked at the grapes with longing eyes and licked his chops. But the bunches were too high for him and he was feeling weak. So he sat down for a while to take some rest. On feeling refreshed, he jumped as high as he could, to get at the grapes. But he failed to reach them.
Then he again rested for some time and made another bold attempt, but was unlucky for the second time.
Forced to give up trying anymore, he just walked away and instead of accepting his failure, he remarked "the grapes appeared to be ripe and juicy, but now I see them to be quite sour."
It's easy to despise what you cannot have.