The people that deserve the most suspicion are the ones who lie the most. The people who lie the most are salespeople. Not all salespeople lie, but the honest ones are hard to find. Who is the most famous salesman in the United States today?

When a salesman makes some kind of claim, the first thing you should ask him is “Can you show me some evidence that your claim is true?” If he does not show you evidence and just says things like “Everybody knows this is true,” the smart thing to do is to keep your money and walk away.

Anyone can be forgiven, even the worst salesman, but fir...