The Fox And The Grapes by Aesop

The Fox and the Grapes (Perry Index 15) is one of the oldest and most influential of Aesop’s fables, and the origin of the English expression "sour grapes." The fable appears in the earliest Greek collections and was retold by Phaedrus in Latin verse (1st century CE) and by Jean de La Fontaine as Le Renard et les Raisins(1668). Modern psychologists cite it as the earliest illustration of cognitive dissonance — the mental discomfort of holding contradictory beliefs (wanting the grapes but being unable to reach them), resolved by changing one’s attitude ("they’re sour anyway").