In fact, I think that 'work / life balance' is precisely there, because teamwork costs energy and spending time away from each other is as important as spending time together, and there is more to life than code.
A couple of years ago I spent some time re-factoring a huge code-base that had totally gone off the rails. The guy that ran the project and I clashed quite badly when it came to the code and our approach to it (but since he asked me to help it was fairly clear that he was out of his depth from a programming perspective). When I got there there was no version control, the code was a giant hairball and literally nothing worked.
We spent the better part of two years untangling the mess and at each and every turn he'd dig in and make progress just about impossible. I tried very hard to keep my cool in all this and to just resort to facts rather than ego and I think that's the only reason that we did not end up in an actual fight.
Being a team player can be super hard, especially when everything is phrased in terms of 'your way or my way'. It eats up a huge amount of energy that could be used more productively and it tends to make it hard to leave the job without taking it home every day.
The hardest person I had to work with was someone who was super picky about using the right words for all social situations. If you referred to something as "your way" They would make a rather large deal of it. Most of the time, I was just trying to identify one of the two choices.
I mean, uh, the person in question was certainly worth working with, in spite of their social issues, and certainly, learning less confrontational language, you know, language less likely to set off other people is a worthwhile goal, but my point is just that if you spend too much time concentrating on the connotations of the words, rather than on the denotations, well, you can become pretty difficult to deal with for anyone who isn't used to walking on your particular brand of eggshells. Yeah, if you are good enough, we'll deal with it, but don't pretend that making a big deal out of connotations rather than denotations makes you easier to work with. It's quite the opposite.
I mean, I totally agree that minimizing ego should be a goal... but I also think it's disingenuous to pretend we don't have ego at all. We all have ego. It sucks. but it is. lying about it won't help. Acknowledging it and trying to move past it might.
Before that it was a bit of a madhouse, but they got a ton done. Which I guess confirms your point.