Some of us just don't enjoy socializing with whoever happens to be around more than we would enjoy just not socializing. I have had some good relationships with some of my co workers but I haven't made any real friends at my current job of ten years. And the people that talk the most tend to be the ones I find the most difficult to relate to, whether it's because they only want to talk about one thing (football or hunting generally) or all of their jokes assume everyone else is racist too. The specifics here have to do with my location but it seems like a wide enough issue that most of my real friends experience similar issues at their jobs as well.