I really can't remember how the subject came up, but on the way to dropping my son off at a friend's house for a sleepover, we got on the subject of taxes (what did you expect, we can't talk about Madden 11 all the time?) and he was quite surprised to hear that the more money you make, the higher percent you paid in income tax: it was plainly unfair to him, and he said,
"you did the work, you earned the money, shouldn't you get to decide how you spend it?"
I replied "as long as it's not illegal or immoral, I agree. If a rich person wants to buy a brand new pair of socks every day, I may think that's stupid, but it's their money."
I also let him know how proud I was that he understood something that many elected (and citizen) folks don't.