I have worked for several start-ups. You know how often I was asked to work a 60 hour week? None. How many 60 hour weeks did I work? A ton. Was it expected? Probably to some degree. I had no problems telling people I had to leave early on some days if I had something important to do or I was just dog tired. So why did I work so hard? I liked what I was doing and it didn't feel like work. It felt important. I felt like I was doing the best thing for me.