The ontological status of the world and our place in it being as indeterminate as they are, it is no great surprise that wishful thinking has long been a popular human activity. Alas, what passes for reality is a many-splintered thing, and so can be shaped, subjectively at least, by our self-willed orientation to it.
Sometimes wishful thinking is pointed toward the future, which can be a good thing: We often cannot summon our potential nobility unless we can envision a use for it. Our happiness depends on it to no small degree, as well; as Lincoln supposedly said: “Folks are usually about as happy as they make their minds up to be.”
Sometimes, however, wishful thinking is pointed backward, where it works mainly as ego protection against the onslaught of contrary evidence. The most common manner of operation is well described by one of La Rochefoucauld’s most famous aphorisms: “We confess to little faults only to persuade ourselves that we have no great ones.”