At the first hint of something that reminds me of my childhood, I absolutely freak out.
If a room looks a bit untidy (there's something on a surface) or an item of furniture interferes with the 'flow' of the area because DP has moved it, it's going to turn into the filthy hoarder's house and I'll be walled in with multiple bits of furniture stacked three deep on every wall and have to squeeze along little goat paths up the stairs.
If DP inadvertently buys the same washing powder, fabric softener, soap, toothpaste or cleaning materials, the smell makes me feel that she's coming to get me and I have to remove every trace, replacing the products and rewashing/cleaning everything again.
If he is quiet (which he is as a rule, quite naturally) but it's after we've disagreed about something, if he doesn't respond to me straight away and give me a hug, I think he's going to ignore me for days before exploding. He changed his learned response of 'stay out of the way and try not to draw attention to yourself and it'll go away/calm down' because I got so freaked out by it.
Worst of all was when he raised his voice for the one and only time. Instead of arguing back, walking away, answering normally to defuse it or telling him to fuck off because I was right, I completely lost my shit. As soon as his voice went over his usual low volume, everything came crumbling down - he was going to smash up the house, throw things everywhere, hit me, tell me what a disgusting embarrassment I was and how I should never have been born - and I was terrified and near hysterical, begging him to stop, apologising, cowering away from him when he realised how scared I was and wanted to hug me and apologise.
I get it to some extent at work - if there is (and there always is in an office in my experience) a small woman who is confrontational in private, but nice as pie to men anybody who has a position of authority and tends to stride along before barking at me to explain what I'm doing/question why I've done something/why I had to ask a particular question, etc, I want to hide under my desk the moment I hear her approaching and if I hear a female voice raised in the distance, I'm upset, furious and near to tears for whoever is on the receiving end of it.
I had somebody call me and shout down the phone at me whilst self isolating over something - whilst I did handle it well in my opinion, as I said it wasn't appropriate and notified my line manager (it's not ever happened again), what they didn't see was that I was shaking and tearful at the thought of it for three days afterwards. Because it sent me straight back there and it meant I wasn't safe at work, as an adult.
That level of dysfunction really pisses me off - all because of 4 foot 11 and a half of venom for 18 years, I can't even handle a mildly annoyed DP or a bit of a dick of a colleague without thinking I'm about to get battered around the head.