The Fox and the Grapes.
Reading edition
A famished Fox saw some clusters of ripe black grapes hanging from a trellised vine. She resorted to all her tricks to get at them, but wearied herself in vain, for she could not reach them. At last she turned away, beguiling herself of her disappointment, and saying: "The Grapes are sour, and not ripe as I thought."
Revile not things beyond your reach.