In "Self-poisoning of the mind" Jon Elster uses the Thales olive incident as an example of a perverse cognitive bias:

In his retelling of the [Thales olive] story, de Montaigne (1991, p. 153) explicitly asserts that when he condemned money-making, Thales ‘was accused of sour grapes like the fox’. Although Thales wanted to ‘show the world’ that the accusation was unfounded, one could also imagine that he had made a fortune in order to demonstrate to himself that his philosophy was not the product of sour grapes. Not content with thinking that he could have acquired riches had he wanted to, he might have decided to actually acquire them to deflect self-suspicion. [Emphasis in original.]

What Elster is pushing is that, since we are aware we edit reality to suit our self-images, we constantly suspect ourselves of doing so, and perversely believe the worst of ourselves on very flimsy evidence.