Well, first off, I haven't put any numbers on it, so 60 hours is made up. Second, I'm not saying I'm going to "slack" during the 40 and waste 20 hours, I'm just talking about doing a normal job (with a normal amount of slacking interspersed. Let's not ignore that I'm posting on HN during my standard business hours at this very moment). And third, I am capable of adjusting how much time I need for hobbies and family on any given day, and sometimes I'll happily trade a saturday with hobbies or family to do some good work. I honestly don't know what it would be like to have a job that I never ever felt passionate enough about to willingly put in a little extracurricular time. It sounds horrible.