My father is a proper narcissist and he raised me to believe I was worthless as well. He also delighted in psychologically and emotionally abusing me since very early in childhood well into adulthood. Like screaming at me until he provoked an anxiety attack, etc. It wasn't out of frustration, you could see in the expression on his face that he genuinely enjoyed it.
People like that are impervious to lessons. They are immune to fuck you's. Idk if your father is like that. If he is, you could leave a note, a letter or an entire novel and he'd still be convinced that he was the best father in the history of mankind. He might even use it for pity points after your death, showing it around to prove to everyone how bad he had it with an ungrateful and spiteful child like you. If he's not like that, he'll have to live the rest of his life with the most tremendous guilt a parent can ever imagine. At that point, even if he learns the lesson, what good will it do?
I can't tell you what you should or shouldn't do because I think it's up to you. You should do whatever is best for you, and I don't know what that is. It's why I usually avoid threads like this. All I can do is give advice based on my experience, which is obviously bound to differ from yours. Personally I will not be leaving any negative notes to any of the people who purposely and maliciously messed up my life. But you have to do what feels right to you. You can even write him the note you want and then destroy it. I've done that several times and it really is cathartic. I feel no need to perpetuate any negativity after my passing. When I'm gone it won't matter to me. It's while I'm alive that I have to seek justice and validation and as long as it's not destructive I give myself permission to do that. But my death is something I want to be peaceful, so my final acts will be peaceful too.
