<i>...when a merchant and a customer exchange money for goods, each thanks the other, showing that the transaction is not only voluntary, but mutually beneficial.</i><p>WTF? I'm friendly and thank <i>cashiers</i> because they're almost certainly minimum-wage, part-time, no-benefits, paycheck-to-paycheck folks dealing with unfriendly people all day long. I'm not thanking them or by proxy their bosses or their company for the transaction, I'm not genuflecting to capitalism, I'm recognizing the humanity of the individual.