Some people don't know how to deal with conflict in a constructive way, so they resort to games. Games can be in the form of manipulation, gas lighting, passive aggressive behaviour. I don't think they sit around trying to figure out how to do this to you. I think they just do it because they do that with everyone. I'm not sure your situation, but for me, I avoid people who engage in that. If you can't do that, then at least you know what you are dealing with and that should give you some protection in knowing it's not you that carries the problem.