The left has a weakness for despair, the right, for delusion.
It requires a huge degree of self-belief, a considerable lack of self-awareness, and a touch of delusion.
For one thing, it shows an overhealthy self-regard that crosses into delusion.
"act of misleading someone," early 15c.; as a form of mental derangement, 1550s, from Latin delusionem (nominative delusio) "a deceiving," noun of action from past participle stem of deludere (see delude).
Technically, delusion is a belief that, though false, has been surrendered to and accepted by the whole mind as a truth; illusion is an impression that, though false, is entertained provisionally on the recommendation of the senses or the imagination, but awaits full acceptance and may not influence action. Delusions of grandeur, the exact phrase, is recorded from 1840, though the two words were in close association for some time before that.
delusion de·lu·sion (dĭ-lōō'zhən)
A false belief strongly held in spite of invalidating evidence, especially as a symptom of mental illness.