I spent 19 years thinking that if I didn't devote myself to my job 100% I was a loser.
In a town like Washington DC the first question at cocktail parties is always " what do you do? "
Stay at home Mom is considered a kiss of death answer, unless you are married to someone like George Stephanopoulus, and then it's okay. It's called the coat tails effect.
When some asks how you are, the appropriate answer is "insanely busy at work" -- it is very politically incorrect to say bored or underutilized or that things are simply slow.
There is a distinct caste system. For example, if you are a Federal employee with a ranking below GS-15 (pay band and grade level) you are considered an underachiever. If you are a Schedule C (political appointment) or SES (Senior Executive Service) you are considered someone worth getting to know.
In DC achieving work/life balance is considred an excuse for those who just simply lacked the talent to get ahead and this is a means of self-justification.
After my last job, which fried me to a complete crisp with way too much travel and stress, I vowed never again. It took a huge toll on my health (which I am still recovering from 18 months later) and I am sick of having no quality of life. No job is that interesting or that important (unless you are Condaleeza Rice) to sacrafice your life.
It has taken me a long time to get to this conclusion - perhaps it seems obvious, but for me it wasn't. And to be honest, I still feel guilty about not working harder or trying to "get ahead." When I read about someone I know and that they have just been appointed Chief of Staff to Senator So-and-So's office I have a twinge, but then I take a deep breadth and go do some Yoga and it helps.