One thing that's commonly not discussed is the fact that for those of us who are naturally introverted, putting on the socially outgoing facade requires a lot of energy ... and to a lesser extent, even being sociable with those we love can be hard when your brain is completely focused on achieving something.

It's funny (to me at least), that my brain can be perfectly happy being alone for eight to ten hours a day. When the work is interesting, time is compressed and my surroundings "blur". My kids have figured out that if I don't answer them, it's generally because I really never heard them.

I agree with you. Being sociable for its sake can be its own stressor. Better to hang with people where you can be authentic, be yourself. How one finds balance and happiness in their work-life make up will be different for each person. There is no one-size-fits all lifestyle :-)