[ipnon]

The prisoner's dilemma shows us that the optimal strategy is screwing everyone else over if you aren't certain that they won't do the same to you.

[dwaltrip]

The prisoner's dilemma is a very insufficient model for the complexity of human life...

The iterated prisoner's dilemma is a little better. It's still just a toy model, of course. However, you might be interested to find that those who only screw everyone else over don't fair well in the iterated version.