He’s an example I remember from my textbook. Let’s say you are really passionate about protecting the environment. But after a picnic outdoors you don’t take your trash to the garbage can, you just threw it on the ground. You feel guilty for doing that. The guilt you feel from discrepancy between your values (environmental protection) and your actions (littering) is cognitive dissonance.

The question is, how does this dissonance motivate you to alleviate that guilt? Do you change your behavior, for example, by going back and picking up after your trash properly? Or does it make you change your underlying belief system (“maybe protecting the environment wasn’t so important to me after all”).