Everything about us kids pissed him off but what got us the worst ass beatings was when we tried to stop him from beating our mom.
I would have killed him.
A good friend of mine's mother had a dad that occasionally beat on her mother (my friend's grandmother). One day she'd had enough of seeing her mother beaten and took a knife to the father while he was in the process of beating her mom. She finished it and mom wasn't beaten any more. Good riddance to bad trash.