In a way, either their neglect or their conscious training for violence does end up causing violence (even though it was a play on words, ik lol). Haha, exactly! My cat will rub up against me, and act all nice, and then I'll pet him... And out of nowhere, BOOM, bite to the hand Don't know what he's doing. I see it with friends' cats, too.
And why do everyone's cats scratch them? Mine only "Scratches" when she get;s comfy, which, unfortunately, is on mi shoulder while I am sitting, sorta like a parrot.
We have two cats. A ginger tom named Popeye who is quite placid these days but was a real psycho when he was younger. He would hide in wait then pounce on people and lock his arms and legs around their limbs trying to bring them down like a buffalo. Thankfully he mellowed with age. We also have a black female named Zeb who has always been as mellow as they come. She is really affectionate and talkative and even tolerated the sort of attention you might expect a cat to get from young children.
So can dogs (dogs get it much more frequently) and humans... You must be feeding your cat(s) off the street food or something to get it 5 times...