This is related, and I found this particular post from another thread:

This makes sense, as I still get the chance to write on her timeline though, as well as like some of her photos. To me, it no longer matters whether she replies or likes my posts. Unfriending her is only a sure way to ruin our friendship, as it is like a carrot and stick dangling right above my head as bait. I don't expect her to give anything back in return, though the gratification is more if she does.