Unfortunately, ESL in China can bring one into contact with the strangest, most messed up human beings that one can possibly imagine. Much is said about the dishonest people that happen to be Chinese; yet the foreigners that you are likely to encounter are often far worse. It can make one lose their faith in humanity and become less trusting of others, you have to be careful not to become one of these people yourself. If you are ever unlucky enough to work in a private training centre (actually, public universities are sometimes not much better); you may find it not quite unlike working in a mental asylum and it really can drive you insane...

I wouldn't ever suggest shunning contact with absolutely all FTs; but avoiding the general foreign teacher crowd in a city, maybe.