Perhaps it is a cultural thing? Because here people hang out with co-workers all the time. When I have worked it was not unusual for co-workers to grab a drink together after work. We regularly got together on days off. I used to take co-workers with me on hiking and kayaking outings. I used to have dinner parties with open invitations to the other singles I worked with, and so on. This was not just a thing I did, we did. But that was amongst peers. Never would I socialise with people I had leadership roles over. That is just a big can of worms that should be left closed. Most companies even have rules against such a thing.