I think it depends entirely on what your idea of revenge is. I personally think that being successful and living well is the best revenge you can have on the people who have betrayed or wronged you. Back in 2014, I put my two-weeks in at the hotel because my manager had gotten (wrongfully, I believe) upset at something I did and brought me into his office to scream at me straight for a good 5-10 minutes. The next time I saw him, I was working for the parliamentary secretary to the Minister of Finance. Obviously you need to be gracious, but there's nothing more satisfying than success - and it doesn't hurt anybody.