The con is a kind of jiu-jitsu that turns the sucker's own greed into its principal weapon. The greedier you are the more likely you are to be conned, and for the greater a sum. Since people regularly dispose of their intelligence in their rush to be swindled, and then turn right around and do it again, humans must want to be duped. Institutionalized wishful thinking - the stock market, religion, advertising - is after all a cornerstone of our system.