I would say it is more a statement of sad it is for you that you hit a few brick walls and gave up. if everyone that ever encountered a few brick walls gave up the world would be a pretty miserable place to live in. i am sure Rosa Parks sitting at the front of the bus hit more than a few brick walls but her force of conviction brought about a small change that led to even larger changes. I wonder what would have happened if she gave up and retired herself to the fact that she could never change anything.
If I was to ever leave this country and go back to Canada i am sure i would go back to my previous job of working in child protection services. Talk to me about hitting brick walls after you have seen a childs corpse after they have been neglected by their parents or even worse after they have been actively abused by their parents.
Teaching in a training school might not have been the best experience for you but again that is not every persons experience. Before dismissing the whole industry try your best to understand that ther are places that really do make an effort to help their students as well as the teachers.
York may not be the best school in China but am 100 % sure it is not even close to being one of the worst.