I think there is a difference between working long hours and being 'married' to your work. People who are passionate about work will end up spending more time on their craft then those who are not, but they aren't always working. For example I read HN, and feel that it makes me better at work, but it's not work. I spend time outside of work doing things that are work like, but not my job because I really like what I do. No matter how much I like what I do, I can work long hours on any of it without getting burnt out, and if I do that for long periods of time I can feel the psychological drain.
