Long Work Days

I spent 14 hours on Monday and 11 hours today either directly on work, or traveling to some place with colleagues to work. Those are long days. So the question comes to mind: Is it worth it? Well, I'm still here, or working there, as the case may be. The US in general, and the Midwest, or East, or Silicon Valley has the reputation of hard work equaling results because that's the reality. The 40 hour work week? I'm not sure to how many people that applies.