> Would an individual pay $500 more in taxes than they are required to out of the goodness of their heart and belief in the American government?

I've done it. I also let the shopkeepers make "mistaken" change when I visited Nepal. Sometimes I tip $5 even when I buy less than $25 worth of food at a restaurant. Maybe I'm a moron, but I think of money as a tool and when I can afford it I am happy to help others accomplish their goals. In the case of taxes many of the government's goals are aligned with mine so I'm even happier to contribute.