Cognitive dissonance is what the social psychologist tell us is that uncomfortable feeling caused by holding two contradictory ideas simultaneously. This uncomfortable situation often results in feelings of anxiety, shame, anger, guilt, embarrassment and stress. In order to achieve some sort of cognitive harmony, individuals often turn to confirmation bias, which is a tendency for people to prefer information that confirms their preconceptions or hypotheses, independently of whether they are true. They also deny disconfirming evidence.
When times are tough populism offers anti-establishment or anti-intellectual solutions or policies that appeal to the common person. Populist leaders know well how to fan the flames of populist outrage by validating the delusional beliefs that soothe the sufferers of cognitive dissonance.
We can only hope that the current populist outrage, both on the right and the left, will be short lived. Historically, your average populist revolution does not end well.