The worst, absolutely worst, thing you can do is to let the other person know they have the upper hand. Personally or professionally. I am talking professionally at the moment. Never let your boss or anyone for that matter know they can manipulate you into submission or selling your pride. Because nothing in this world is more important then your respect and your peace of mind. I have an issue. I let people reign over my head, mind screwing me until I collapse. And then I hate myself for being so docile. And it begins a downward spiral. But in actuality, come to think of it, it is my fault. I allowed someone to reign supreme until I caved and collapsed. So. It. Is. My. Fault.
But how do you fix it? By making an active effort. By letting them know, you were not born to be a minion. You are a thinking walking breathing opinionated human being. And manipulation does nothing to you. If anything, you laugh in the face of domination. Because you are not a wall that can be broken, you are a rubber band, that when pulled will not break, it will hurt you back.