I just don't interact with a single colleague unless pushed to (private school here). I sit in my own little cavern and teach when I gotta teach.

I used to interact and go to dinner etc years back, but I just get so tired of the work talk and never engaged in it. From the beginning of my adult life I can't remember a single time I've taken work outside of work. I'd always move the conversation to something else, like how there are ants with door-heads!