Trust me - compared to working adults, you do. :)

As someone who was in high school just a few years ago and am now working I would argue that is definitely not true. High school can quite easily take a lot more time than work, especially if you are an honors student or do any extra-curricular activities. I would wake up at 6 am, be at school at 6:45am, and leave school at 5pm most days of the week due to sports and class. Then I would have 2-5 hours of homework to do. Now, working for a large company is 40-50 hours a week, 9am-6pm with little work after hours.

Depends on the job, some of us do a lot more than 40.

Getting married and having children will make you reassess your statements. Heck, just getting married will. Of course, I am assuming that you are single.