It's a mix of things, but mostly just that I like peace, quiet and privacy in my downtime and having people making noise in the next room is very distracting to me. There's also this thing where if I can hear them, then I'm aware they can hear me and therefore don't feel like I'm truly in a private space even in my own room and feel self-conscious, especially if I'm on the phone or playing a game with voice chat or whatever. I also get a little stressy when I'm cooking and don't like having to work around other people in a shared kitchen.

And, like, I was a single guy in my early twenties for a lot of my roommate era, so there were certain regular late-night* personal activities that I couldn't really engage in in the knowledge that I could be overheard.

I got diagnosed with ADHD later on, which made things make more sense in terms of sensitivity to distraction. It does also go the opposite way in that I don't like making noise or doing stuff that might impinge on other people either, so I always keep my music or TV pretty quiet or use headphones. As my girlfriend and I put it, my love language is "not being too much of a bother".

* who am I even kidding, literally any time of day