Do founders have to have a miserable life in order to succeed?

Quoting Paul Graham from Founders at Work :

One thing I regret is how pathetic we were during much of this whole process… I also kind of regret being a zombie for several years straight. I really had no life during Viaweb.

Is it necessary for a founder to be a zombie in order to succeed, or, can he/she do it without being a zombie?

Side Projects

Having heard a million times that projects which become successful startups are those started as side-projects, famous examples would be Google, Yahoo, Apple.

Then, when does that side project sucks it all out of you and makes you a zombie? And why do people stop having fun(going out for a movie etc.) after a while?

I think there are various reasons that causes the founders to be a zombie:

Pressures

1. Time to market: They are forced by the fear of loosing out to a competitor to work too hard.
2. VC pressure: VC wants results for the money they have put in.
3. Maintain the Momentum: You fear that the momentum you have now may not come tomorrow.

And Startups are hard

Building/Killing the product, hiring people, firing your buddy. All of these things are hard and makes a founder crazy doing it the first time.

Exceptions

I bet there are exceptions—the startup founder, who did not have to be zombie in order to do be successful. But the ratio might be heavily skewed. I would like to hear their story.