I have an enemy.
Actually, being a combative and outspoken person, I probably have quite a few enemies I don’t know about. But I do know about this one, because he announced to all our circle that he was never going to deal with me again, and ceremonially unfriended me on Facebook.  When I meet him in a public place, he responds to my polite hello with a grunt as he walks pointedly away.
Recently I had the opportunity to do my enemy a favour, and recommend him for some much needed work (needed by him, that is). As I told my colleagues, when I suggested he be approached for the work, they could really trust my recommendation, because I couldn’t be accused of doing a favour for a friend. He’ll never know that I pushed his case, and I’m quite content that he should not.

I found this strangely satisfying.
I shouldn’t have been surprised. In the gospels of Matthew and Luke we read that Jesus urged his followers:  “Love your enemies. Do good to them, and lend to them, without expecting to get anything back.” (I think lending to one’s enemies might be taking things a bit far, but this is Jesus we’re quoting here.)  However, when we get the same exhortation transmitted by the much more rebarbative (lovely word – go on, Google it! ) St Paul, we get "If your enemy is hungry, feed him; if he is thirsty, give him something to drink. In doing this, you will heap burning coals on his head."
So you see, you can be kind and Christian and have some rather unchristian satisfaction at the same time!