My colleagues at work are great company for most- very social, great sense of humour, and all get along well. So we do beer nights and movie nights and all of that goes very well. I am enjoying it because I was in a one-person lab for most of grad-school so this is awesome. But I know for sure that I will never get into close friendships with any of them. Like most big groups, there's a significant amount of back-biting and bitching here, something I just don't have the stomach for. So while they are super-nice to you on your face, the minute one person in the mix is missing s/he becomes the subject of conversation and ridicule. It's not like that's all they do, but they do it a lot. They recycle the same nasty jokes about a person, and when the subject of their criticism is back, suddenly its all sugary sweetness. I thought I had left behind this kind of behaviour in high school. These people here I'm talking about are either grad students or post-docs. It disgusts me every time I see it, and of course the thought does cross my mind as to what they discuss about me when I'm missing. I don't really care though.
I have dealt with it mostly by resorting to plugging in my earphones and going back to work when this begins. Or just nodding and smiling. A few times I have called the person out on it. Like when my bay mate went into bitching mode about xyz "You know I really like xyz and she's a great friend and very smart but she is slacking at her job and it affects the rest of us.." I told my baymate that if I were a good friend I'd rather be told in the face that I was not doing something right. My bay mate did not take that well at all, as I anticipated but I was getting sick of her bitching. I have also broken away a bit and made friends with people from neighbouring labs to go to lunch or chat with. That does help to keep it healthy.
Sometimes the sheer superficiality of their groupisms, affections, friendships and congeniality irritates the hell out of me. Other times I feel that I need to stop being so uptight about it and just accept it as a part of group dynamics. To some extent gossip is healthy and natural, and I guess we all need to vent and bitch. But the two-faced-ness of it is a bit much for me to take. Eventually I think I'll get thick-skinned to it, its already bothering me a lot less now.