I get where you're coming from OP. I live in a back to back end terrace. Our neighbours at the back are loooouuuud.
Two kids, we hear them playing sometimes, I don't mind that. It's nothing too unbearable. I think one of them must have been chucking a ball around the other night when I was trying to get DD to sleep but I tapped on the wall and it stopped.
The mother though, jesus, she's a shouter. Not as bad as she once was but at one point it was every single morning, shouting and screaming and swearing at the kids. It did hit definite verbal abuse at one point and I reported her to SS. It calmed a little after that.
But I get completely where you're coming from with the tense feeling, the anxiousness, the knot in my stomach every time I hear her. My DH isn't as bothered by it as I am but I think he's always liked this house more than me anyway (we own, been here nearly 2 years).
The people who had the house before us lived here for like 20 years. When we looked round I asked about the neighbours and she said "oh they're fine, young family at the back, you hear her shouting at the kids occasionally you know" and I wish wish wish I'd pushed her for more info on that. But then occasional shouting is normal, you just don't expect screaming several times a day...
Potential light at the end of the tunnel. We know they rent so there's always the hope they might move! DH reckons he heard them talking about a mortgage the other day but I don't know if they actually were...