This is really ground breaking stuff. You mean to tell me that instead of enjoying my friends and family and experiencing all that life has to offer, I can simply work on my Web app? Whoa. Seriously though, why sacrifice so much for a mere 'side-project'? Either get a better/bigger idea and make IT your full-time work, or find a 40hr./week job that is fulfilling to you. There is no other side project that will be as…
I find it interesting that you react so strongly to this. Is it your belief that everybody should be working a 40 hour work week, and spending the rest of the time with their family? If so I suspect you're in the minority on HN.
I feel like this mentality is being bred in the startup culture solely for the benefit of companies with very little thought given to the potential impact it can have on someone's life. Working 40 hours a week you probably have ~30-35% of your life free to do with as you please (after sleep, work, commute, etc.). I'll let you do the math from there when you work 60-80 hours. We don't get enough sleep. We don't get enough vacation time. We don't have enough time to recover.
I feel that humans need balance in their lives. Balance will provide fresh perspective and allow you to continue being good at what you do. You have to "stop and smell the roses" as they say. I also feel like today's society is out of balance.
I feel like 40 hours is the most anyone should ever have to work. I feel like even that is too much. Unfortunately it's necessary in today's society. Mostly because a lot of what we develop and create doesn't actually allow us to work less. Usually it just makes a couple dudes rich.