A great hero. I encourage anyone to read Chuck Yeager's autobiography. Besides breaking the sound barrier, he was a WW2 ace, and later flew fighter missions in Vietnam War after his test pilot days.
I took 3 years off to pursue a non-technical business. On returning, I researched new technologies I was interested in, and created my own hobby/open-source projects in those areas. This allowed me to ramp back and learn something current, and also I was able to share these example with potential employers.
Wrote a blog post on this a while back[0]. Short answer: no, not friends with my manager, nor my subordinates. We get along great, and have a good time at work-social events, but that's the end.
I disagree with a lot the points in your article. The things you listed as cons with having office "friends" all sound like things no real "friend" would do. I don't generally use social media, so maybe I don't understand that aspect, but honestly if someone came to work and gossiped about me, they wouldn't be considered a friend. This article seems to specifically mean Facebook friends so I guess my opinion isn't super relevant as I don't use Facebook.