Catherine Rampell digs up a 2011 study on work hours:
Americans tend to overestimate how many hours they work in a typical week by about 5 to 10 percent, according to a Labor Department study, with the biggest exaggerators being people who work longer weeks.
Yglesias's interest is piqued:
People who think they're working 40 hours a week typically work closer to 37. But people who think they're working over 60 hours a week are typically adding 10 or more hours to their real amount of labor time. Researchers think this reflects a "social desirability" effect where it's considered good to be working really long hours.
The Dish 