"But yes my fathers mood could turn in a nanosecond so we all were "on alert" as a result."
My dads mood is still quite volatile. He gave me the danger feeling a lot as a kid, when I would just know to be quiet and behave or else. It was like a black cloud would appear over him, iyswim. My grandad and stepdad too, but I wasn't afraid of them the same way (I didn't see them as authority figures, but knew they'd shout and give my mum/gran a hard time if I pushed too far). It's the same sort of "get ready to run" feeling my ex and the creepy window cleaner give me.
As an adult non of my male relatives scare me anymore, (unless I'm in the car with my dad while he's driving, when I sometimes fear he'll get so worked up, he'll crash).
My ex scared the shit out of me when he lived here, but then he was destructive, violent, having frequent psychotic episodes at one point, and I think loosing touch with reality in general. It was awful when he'd come home some days, and I'd take one look at him and think "oh ffs, here we go again", before he'd even said a word, just like when I lived at home, and I'd do the same with my various male relatives, only ex's behaviour was 100x worse.
I wonder if I am hypervigilant now as a result of all this? I find it really hard to relax, and am always tense. I used to get severe shakes from random adrenaline rushes, when I felt threatened, though that's eased now. It's quite hard to sneak up on me (I'll often sense my cat come into the room, look up and yup, there she is), or know when I'm being watched.
If so, it's not a bad silver lining, but not worth years of walking on egg shells to develop. Although I do think with some people, it's more inate? Maybe people with anxiety are also hypervigilant but for different reasons, etc?