> If they sell your debt to a debt collector, have fun with that.

If you have the time and volition, and aren't terribly concerned with your credit rating, it can actually be quite fun because a lot of debt collectors routinely violate the law in terms of what they're allowed to do, and you can usually make some money off them in that way.

Of course, I'm talking about small debts. If you owe enough money, the collector will probably sue you, and that truly is no fun.