Lisa WIlliams provided an interesting link to this Science article which suggests that most people are very poor at detecting liars. Catastrophically, most people actually think they are good at detecting lies.

Kind of like how more than half the drivers on the road think they are above average in skill.

Or, in the same vein:

“Thus, those who are skilled think that they are skilled because they are competent to judge. Those who are unskilled think that they are skilled because they are incompetent to judge. Therefore, whoever you are, you think that you are skilled, and there is no internal way of finding out if you are deluding yourself. The possibility that we are, in fact, all duffers goes a long way toward explaining the sorry state of so many things in the world, in spite of the fact that we each think we could do better if only we had some say in the matter.”

Jef Raskin