My property has the thinnest walls ever anyway and I think my neighbour must have some sort of issue with their internal doors not closing properly because they resort to slamming them all repeatedly until it closes. Last night at 11pm they slammed their bedroom door no less than five times waking me up and making my walls shake. They have dc and god knows how they sleep through this. We get on ok to the extent of saying hi to each other outside but I think I’m going to have to say something. Is this U? How can I say something in a non confrontational way?