Cognitive Dissonance - If you simultaneously hold two cognitions that are inconsistent, you will experience a feeling of discomfort, or dissonance.
We rationalize our behavior instead of engaging in rational behavior.
Analogous to hunger
We are naturally motivated to eliminate it.
Example
I enjoy smoking; smoking leads to lung cancer.
Sam thinks she’s environmentalist and tries to save energy and water consumption. But her room mate is constantly wasting energy and water