Have you ever spoken to the neighbour? If not, maybe try and maneouvre yourself into a situation where you can say hello. Sometimes it's a bit like sitting in your car - you think you're insulated from actual people and can behave badly...until you realise that the person you just abused is actually someone you work with, haha. Whenever any shouting commences in my house I think of the new next-door neighbours who seem very nice and normal, unlike us. This at least prompts me to shut the windows. On the other side we have a retired woman and her incredibly shouty daughter, who has now reproduced and shows every sign of becoming equally shouty towards her little girl. I did once knock on the door and say that 'someone over the back' had asked me whether the middle one had hit the older one. Because we heard her do it, when all the windows were open. She hasn't done it since.