From simplypsychology.org: "Leon Festinger (1957) proposed cognitive dissonance theory, which states that a powerful motive to maintain cognitive consistency can give rise to irrational and sometimes maladaptive behavior. According to Festinger, we hold many cognitions about the world and ourselves; when they clash, a discrepancy is evoked, resulting in a state of tension known as cognitive dissonance. As the experience of dissonance is unpleasant, we are motivated to reduce or eliminate it, and achieve consonance (i.e. agreement).
"Cognitive dissonance was first investigated by Leon Festinger, arising out of a participant observation study of a cult which believed that the earth was going to be destroyed by a flood, and what happened to its members — particularly the really committed ones who had given up their homes and jobs to work for the cult — when the flood did not happen. While fringe members were more inclined to recognize that they had made fools of themselves and to "put it down to experience", committed members were more likely to re-interpret the evidence to show that they were right all along (the earth was not destroyed because of the faithfulness of the cult members).
(...) Evaluation of Cognitive Dissonance Theory"There has been a great deal of research into cognitive dissonance, providing some interesting and sometimes unexpected findings. It is a theory with very broad applications, showing that we aim for a consistency between attitudes and behaviors, and may not use very rational methods to achieve it. It has the advantage of being testable by scientific means (i.e. experiments).
"However, there is a problem from a scientific point of view, because we cannot physically observe cognitive dissonance, and therefore we cannot objectively measure it (re: behaviorism). Consequently, the term cognitive dissonance is somewhat subjective."There is also some ambiguity (i.e. vagueness) about the term 'dissonance' itself. Is it a perception (as 'cognitive' suggests), or a feeling, or a feeling about a perception? Aronson's revision of the idea of dissonance as inconsistency between a person s self-concept and a cognition about their behavior makes it seem likely that dissonance is really nothing more than guilt." Read the article: Cognitive Dissonance by Saul McLeod, published 2008 Simply Psychology
Maybe it's guilt, or maybe it's just a human condition that comes with being part of this world. That's why we have the serenity prayer. :-)
Related articles: Replicating Dissonance - by Dave Nussbaum
Partisan Psychology: Why Do People Choose Political Loyalties Over Facts? - by Shankar Vedantam, May 9, 2012 NPR
Added on May 10, 2012: Links Debunking Pseudoscience - Professor W. Rory Coker, University of Texas / Christina Valhouli, Columbia University