In general, being friends with your co-workers outside of work is extremely ill-advised and shows that you have absolutely nothing going on in your life beyond the cube walls. It also invites unwanted questions and interest into how you spend your time when you’re not shackled (speaking of, you could be into BDSM for all they know–and it’s really best to keep that part of your existence under wraps).
Though there are many who center their lives around work and the associated cock-sucking that goes with it, hanging out with a co-worker entails far too much involvement with the politics of the office. After a few “sessions” spent together, you’ll soon realize the only thing you really have in common is the fact that you both happen to work at (and hate) the same place. Inevitably, you’ll only end up talking about who’s fucking up at work and who isn’t. It’s all very tedious, and you’d be better off taking up a hobby, even if it’s exercise that forces you to wear Lululemon.