I've often found that the best revenge is to simply BE (or DO) better than the other person you've been slighted by.

Reminds me of a banker I knew many years ago... turned down my business for a loan that would have been very good for the bank... but I was "too young and the business too risky." Somehow, my business was on his call list eight years later, soliciting new customers. With a straight face and no malice I said "I appreciate you thinking of us, but we prefer dealing with a more stable organization... sorry your bank changed hands three times and went into federal receivership." Whereas I doubt he actually connected the dots, it felt good to say that...