A once did some contract work for a company that provided software for Car retailers. Their old software would present some information - comparing the price of cigarettes verse some insurance policy (against a car load), and try to convince people that finance through the dealer was the best. On examining it I realized the original version was not doing the math correctly. On fixing to be accurate, the dealer items were not the obvious best choice. I refused to change it, I was let go. Which was fine by me.