I’ve often wondered about this one:

For a 35-hour workweek, orthodontists earn a median $350,000 a year, according to the Journal of Clinical Orthodontics. General dentists, meanwhile, earn about half as much working 39 hours a week on average, in a much dirtier job.
The difference in their training isn’t like that of a heart surgeon vs. a family-practice doctor. It’s a mere two years, and a vastly rewarding investment if you’re among the chosen: U.S. dental schools have long been criticized for keeping orthodontists in artificially low supply to keep their income up.
This isn’t brain surgery: Orthodontists simply manipulate teeth in a growing child’s mouth — and often leave adjustment work to assistants whose handiwork they merely sign off on. What makes their windfall egregious is that they stick parents with most of the inflated bill, since orthodontia insurance benefits cover nowhere near as large a percentage as for general dentistry.

From this list of the most overpaid jobs. Your mileage may vary on the accuracy of this list.
Via Barry Briggs.