When I was a kid and I read about the Prisoner's dilemma in the context of morality, I was always confused. Surely the moral thing is to confess if you're guilty. If you're guilty, and your accomplice is guilty, the right thing to do is confess to the police so that you can be rightfully punished.
As an adult I understand that this isn't the point of the story, and the police-and-prisoners aspect of the story is completely extraneous to the point trying to be made. Still, I can't help but think that the police-and-prisoners is a bad example of the broader point, since there's always a third set of interests (that of the police, and of society in general) which is callously (and immorally) tossed aside in the phrasing of the problem.