Maybe we Americans work more because we like our jobs. I saw a study once that found 60% of Americans are happy/satisfied with their job. That's amazing to me. I know I love my job. I get to play with million dollar toys, I am responsible for billions of dollars of income per year (not for me, sadly ), I get to push my mind to it's limit (both scientifically and creatively) every day if I want and I'm basically irreplaceble so if I have a problem with a superior, I let them know it... very bluntly. I truly would do most aspects of my job for free if it didn't pay so much (don't tell my boss), so it's no wonder I work the hours I do. Responsibility, creativity, challenges, what's not to like?