The cognitive dissonance theory is something any remotely indecisive person can relate to. Many things play into how much you experience post decision dissonance. The more time you spend on a decision adds to the amount of post decision dissonance you feel. (if you do feel any dissonance) The next is how important the decision. For example, if you’re making the simple decision of “soup or salad” at a restaurant the amount of dissonance would obviously be less then if you were choosing a college to attend. The final part of the dissonance theory is how stuck you are with the decision you make.

An example of post decision dissonance would be in Johnny Depp’s film Donnie Brasco. In this film, Johnny Depp goes undercover as a member of the Italian Mob and becomes too attached to the people he’s supposed to be trying to take down. In the climax of the film, Johnny Depp tries to convince Al Pacino to take the money that he has and just get out of the country. He immidiately regrets the decision because Al Pacino hints at the fact he knows what Johnny is saying and may kill him because of it.

http://youtu.be/_-67OCs6At8