I went to a job interview at a place where they worked 12 hour days but you'd see people were watching eBay, trading stocks, and otherwise wasting time.
Yep, I have seen people that claim to work "all these hours" and that they have to work weekends. But when you watch them work they spend 5-6 hours a day on Facebook, YouTube, etc... Then they get so far behind they have to work extra to make up for the wasted time, yet they complain about all the hours they work. I don't claim to be perfect and I can be guilty of "wondering off" from time to time reading news sites and even Facebook. I just try not to make it an everyday work habit.