Well maybe those physics PhDs are a lot better at socializing than me. I remember spending years of my PhD trying to make friends, going to bars/rock climbing/dances/running clubs etc to try and meet friends, but never got any where, and just feel this crushing depression every day I have to go to work and sit down at a computer for 8 hours. I feel roughly the same in a corporate or academic environment, it's the result of so much being by oneself. Perhaps I shouldn't have gone into computers?
However, Academia for the most part I think is just that sort of environment, I have commiserated with numerous PhD students who say the same thing. If one is into computers, both academia and computer engineering as career tracks are rather isolating, but some seem to like it, vs some get lonely, perhaps it's something psychological, and I'm not really intended to be such an introvert. Who knows.
I don't think academia is a bad career as long as one can get tenure at a good school, or in a good industry lab, so as to work with good people. I guess whether one can take it psychologically just depends on the individual.
Although I do agree that maybe if one had kids+wife or worked hard to be social, the 8 hours of isolation a day wouldn't be that bad. It might even be relaxing! So maybe professor is a good job for one in old age. But still I would worry about causing my students to suffer through isolation.
Actually sorry for my complaints. I thought about this more and realized being a professor is actually pretty good socially. I think being a grad student is just hard, unless you are very outgoing, and can get out of the lab.
I guess I just wanted to caution people that a career in computers and/or academia can very isolating unless one picks the right path. Moderation in all things.