Set and maintain strong, healthy adult boundaries. If somebody blames you for something that you don't control then call them out on it. You don't even have to be mean, just point it out. There's a lot of legal precedence for "But (s)he allowed me to abuse him(her)!" as an excuse for abuse.

Honestly that's the best thing you can do for on-the-job sanity. I understand that people feel they have a right to abuse others, but at some point you really don't have to take it.