Taking the extra work that no one else want to do is not about earning 4 hours of overtime, it's about your future. The harder you work; the more times you volunteer for the jobs that no one else wants; the more times the boss doesn't have to come into the office because he knows you're doing a better job than even she would do -the closer you are to your goal. Unless of course your goal is to sit on  your couch and watch more TV.