My dad was an enabler from a family that is rotten with bipolar disorder. Not a lot of drug use in that family, but bad and manipulative behavior galore. Mom was an enabler from a family full of alcoholism. My brother is the one with bipolar, and he acted crazy since he was old enough to walk and talk, but was not formally diagnosed or put on meds until he was in his late thirties.
My brother constantly picked on and tormented me growing up, and always acted like the perfect little angel the minute dad started to notice. It was like a nasty game with him. And when he terrorized me as a young adult, and I tried to air my grievances with Dad, Dad tried to "enlist me into the effort to help my brother."
For reasons I still cannot fathom, mom and dad always treated my younger brother and sister far better than they treated me. Even my wife noticed this, without any prompting from me.
Dad was extremely toxic and manipulative. He never had any friends. All his socializing was with his parents and siblings, and he loved to meddle and gossip. Mom was just angry all the time, and I received a lot of gratuitous punishment growing up. And both of them had an "If I catch you being happy I'm gonna do everything I can think of to mess up your good time" attitude.
So, yeah. For me, Father's Day is the last day of the U.S. Open golf tournament. Nothing more.