This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / False Memory
The plot of False Memory in general, and its villain in particular. The premise is Paranoia Fuel on its own — how easy could it be, for you to be brainwashed and have no idea? The protagonists are regularly mind raped, and for a long time have no idea, only figuring it out when too many small things cease adding up. And the Big Bad is someone an authority figure people ought to be able to trust. Not only is he screwing with people's minds, he does it for his own entertainment. One of the characters is a happy, successful real estate agent until she sells him his house. He decides she's beautiful and that he wants to keep her, so he implants agoraphobia in her mind and slowly destroys her psyche over the course of eighteen months. He also regularly hypnotizes and rapes her, leaving her with no memory of the assault but with...evidence, leading her to believe she really is losing her mind. When she finally figures out it's him, and looks like she'll be able to get her life back, he catches on and drives her to suicide. And he was doing this to people for two decades before he paid for it, destroying dozens of lives just because he could.