I get a long fantastically with my manager. We do happy hours every other Friday. I'd probably invite him to a BBQ at my house or something like that. But I don't think I consider him a friend. That said, I _am_ friends with some of my old managers, and (as a manager) with some of my old employees.

For current, active working relationships? Nope. We keep that professional distance. Once we no longer work together, I'm open to closer relationships with them. It usually doesn't happen, though.

The truth of the matter is that the thing most of us have in common with one another is that we work together, and once that's no longer true, there's just not that much more to the relationship, and so we inevitably drift apart.