The Fox and the Grapes by Aesop

"The fox who longed for grapes, beholds with pain

The tempting clusters were too high to gain;

Grieved in his heart he forced a careless smile,

And cried ,‘They’re sharp and hardly worth my while"

 

Sour grapes is an expression originating from the Aesop Fable The Fox and the Grapes. It refers to envious behaviour, especially pretending to not care for something one does not or cannot have. http://en.wikipedia.org/wiki/Sour_grapes