I will try and be brief. There was someone I worked with, was friends with for ages, who blocked me on fb. Not unfriended blocked. We do still see each other at work but are in different departments now and are civil. I guess I am asking, should I bring it up, do I apologise as I clearly did something to upset them or should I just let it go and leave them be. I do feel bad but I worry I would just make things worse if I talk about it