The Funny Feeling Inside Your Head …
Cognitive dissonance is an uncomfortable feeling caused by holding two contradictory ideas simultaneously.
Wikipedia: Cognitive dissonance is a psychological state that describes the uncomfortable feeling between what one holds to be true and what one knows to be true. Cognitive dissonance theory is one of the most influential and extensively studied theories in social psychology.
Similar to ambivalence, the term cognitive dissonance describes conflicting thoughts or beliefs (cognitions) that occur:
- at the same time, or
- when engaged in behaviors that conflict with one’s beliefs.
In academic literature, the term refers to attempts to reduce the discomfort of conflicting thoughts, by performing actions that are opposite to one’s beliefs.

Example:
Smokers tend to experience cognitive dissonance because it is widely accepted that cigarettes cause lung cancer, yet virtually everyone wants to live a long and healthy life. In terms of the theory, the desire to live a long life is dissonant with the activity of doing something that will most likely shorten one’s life.
The tension produced by these contradictory ideas can be reduced by quitting smoking, denying the evidence of lung cancer, or justifying one’s smoking. For example, a smoker could rationalize his or her behavior by concluding that everyone dies and so cigarettes do not actually change anything. Or a person could believe that smoking keeps one from gaining weight, which would also be unhealthy.
More from Wikipedia …
See also: How and Why We Lie to Ourselves: Cognitive Dissonance