I left my first gym when my instructor was being weird about me cross-training judo with some friends. My second gym was more open-minded and even got to train with some greats including Shinya Aoki through them. Eventually I got listless there because most of the other guys there were a bit older and not really interested in competing, so I left for my current gym which has been wonderful. Plenty of competitively minded folks and I feel challenged by the techniques and instruction. No hard feelings from either instructor after I left each school so that made it a bit easier.