I'm no financial genius, but even I know that not paying off your entire credit card balance each month is one of the dumbest things you can do. If you pay it off promptly, you enjoy the wonderful convenience of a credit card and a month's worth of float for pretty much free. If you are dumb enough to fall behind, though, you pay through the nose, thus subsidizing us smart folks' use of credit cards. Which may be why nobody in the media has ever complained much about this system -- it's mostly been exploiting dumb people for the last 40 years, and who cares about them?
Is it too much to ask that the law force credit card companies to explain these finance facts in simple English and large type on each bill?