"Truth comes before my own interest."

This is what I like so much about you, Dennis. Your principles are more important to you than doing yourself some favor. You'd give back the five dollars to the poor dumb little cashier who overpaid you your change at the cash register. Sadly, I know too many people who would rationalize that and tell themselves she only had herself to blame for not having learnt any math. In fact, I was married to one of them once.