Ariely discusses how society has few big cheaters but is full of small cheaters who do more collective economic harm than all the big cheaters combined. Such "small" cheating comes as we distance ourselves (and our behavior) from the people we affect, thus making it easier to rationalize the harm we may cause them. Ariely also found, the cheating drops dramatically if the mind is primed with moral code, even if it is not a moral code we personally believe in.
RSA Animate: The Truth About Dishonesty
The Truth About Dishonesty (RSA)
Dan Ariely: Why we think it's OK to cheat and steal (sometimes) (TED)
Dan Ariely: Our buggy moral code
Dan Ariely asks, Are we in control of our decisions?