I dont understand why he would block me on facebook when he is fine with me in person?

[Stella]

Linda...

Do you post a lot of status updates, jokes, ridiculous pictures, or game requests? If you do, it's possible that he doesn't want to be bothered with that. Many people don't like their news feeds cluttered with nonsense, so if you post something, then your friends comment, this guy sees it all. It may have just gotten too much for him.

It's also possible that he doesn't want you, his co-worker, to know too much about his private life. He may have added you at first, then thought better of it after a while. After all, you work together and some things aren't meant for co-workers to see.

Also, remember that just because someone smiles at you all the time doesn't necessarily mean they're being friendly. There's no reason to confront him and ask why he blocked you. That may be a bit too awkward.