> Might be something to do with the workplace setting and money being involved in work. I don't get how transactional behavior in professional settings became taboo when money is at the center of most of it anyways. Nothing personal, just business.

I don't see it as taboo, but when I'm spending eight hours a day with the same group of people, it's just less exhausting if you enjoy spending time with them. If I get to know my teammates and have stuff to talk to them about in downtime, it's less boring than just keeping my head down and not interacting with anyone. Most of my work friends aren't people I'd actively seek to spend time with outside work, and usually I don't keep close contact with them afterwards, but even as someone who's pretty introverted, I would burn out way faster without any sort of social interaction at work.