I realized something the other day.
I've been at a new job for a couple of years, and I've noticed that I've been much less interested in doing activities after work. I get home, and all I want to do is veg out. While some of this I attribute to the realization that I've got over 10 years left until I can retire, there is more to it.
And then I realized that I've been working for over 2 years in an open office environment, as opposed to my previous workplace, where I had a tall cubicle (tall enough for an actual door). I spend all day in the middle of an open room, with several large TVs(mercifully muted), 40-some-odd cow-orkers, and all the attendant noise. I literally have no privacy except when I go to the toilet, or take phone call in one of the little booths we have for that purpose.
I'm an introvert (shock, that a programmer is an introvert!), so all that exposure is exhausting me, so much so that I just want to cocoon myself when I get home.