The only rejection I've gotten that REALLY hurt was for a creative nonfiction piece that had previously been accepted by a magazine. Then the editor asked me a few days before publication if the subject I was writing about was still alive. Since they were, the editor pulled the piece because she didn't want the magazine to have any issues later down the road. Which I understood, but God, it hurt. I've still never found a home for that piece, even though I know it's a good one (they said as much when they initially accepted it) but I did later have another piece published by the same magazine.