A guy a really didn't like from my old office added me as a friend on FB when I left, which TBH, I found a bit weird but because I was still in and out of the office frequently and was/am considering going back there after my current contract finishes I accepted, but put him on a restricted profile.
It just so happens that my old company are doing some work for my new company and I'm having to work quite closely with this guy just now (albeit I get to tell him what to do, hehe).
I had a meeting with him today and we were chatting at the end about the weekend (yes I am capable of being nice to him). I just realised that a photo I'd told him to go have a look at cannot be seen by those on my restricted list....ooops!
Defeat your enemies with success