The most effective revenge is oftentimes one that has absolutely no benefit and little vindication for yourself. A subset of this is the oft-quoted rule which is so much more than appropriate: "The best revenge is living well..." I used this strategem with an ex-friend of mine a number of years ago to great effect. To wit, once I stopped caring, all the things I had been hoping would happen then did so. No sense of vindication, simply a simple removal of an obstacle in one's path. That's the best one can hope for in life. You can never be an instrument of someone else's karma.