I gotta say I've been the lucky recipient of quite a few 0% APR offers on credit, made my revenue and paid off the cards while netting a nice profit to keep some of the extra underlying assets.
What I absolutely hate about the current system are future derivatives, ESPECIALLY short positions. I've earned my fair share of profit using this technique because at the end of the day I've got to keep up with the Joneses and this is clearly a down market, but I think we would all be better off if people weren't making money by betting on companies to fail. The whole practice is disgusting, even if it is done in the spirit of risk management.
It isn't just the betting on companies to fail, it is all of the derivative market(estimated at about 3/4 of all "money" in the world, where money is being made in an opaque and unregulated industry, that has no checks and balances almost and, only some people can actually truly access it. And, it is speculation on what is essentially nothing....
I spent a year earning a master's in finance, and by the end of the year I was left in utter disgust over all the ridiculous derivative products. I vowed to only use my finance knowledge to help my friends and family and refused to accept any offers at big energy companies, investment banks or consulting firms. At least I know how to take advantage of all the tax writeoffs.