When I was in my early 20s my mom got back together with a guy she had been with when I was around the age of five. A real piece of shit that abused cocaine, and been in and out of prison. He never hurt me, mostly I never saw him, but he punched my mom in the nose so hard that he broke it, and split it open around the nostrils. A scar she still carries today. So fifteen or so years later he comes back around and they get together again, and he moves in with my mom. My grandmother at the time was getting to the age where she couldn't live alone any longer as she getting senile, so this dirt bad convinces my mom to convince my grandmother to give him power of attorney over her estate. He sells her house, moves her in with him and my mother, and proceeds to squander ever last dime she had. I tried to intervene, but I was young and broke, and every attempt to get the law involved failed. So I began contemplating murdering him. And I'm not taking casually thinking about it, I'm talking serious planning. I spent countless hours going over every possible method, and every possible outcome, but I would always find a flaw in the plan (usually in the creation of an alibi) that would get me caught. Ultimately I decided that unless I can come up with a air tight plan the risk of incarceration was too great, and there would come a time when my mother would need me, and not from behind bars. So I never did anything. In the end he got caught counterfeiting money, and manufacturing meth, and went back to prison. My mom got her head on right with my help, and over years since we've repaired our lives and our relationship. But that was a very dark time for me.

There's far far more to the story, and many fucked up tails from that time, but the wall of text above sums it up for the most part.