I had this problem myself and got in trouble for it. Work is not really a place for socializing. I wouldn't worry so much about this person's feelings, but your bosses and coworkers might not like it so much? It is safer to just join in group conversations, like when everyone arrives in the morning and are getting coffee and they are all discussing last night's game, or just before they leave for lunch - I NEVER went with them, but I probably should have, at least once in a while, say once a month to start. My T has shown me that I could have fit in with nt's a lot better than I ever thought.