My Neighbor's Late Night Noises Keep Me Up

So I’ve been freelancing from home for a couple of years now. Work has been good lately, but one thing that’s been driving me crazy is the noise from my neighbor's place next door. It’s this guy who comes home super late and starts making all sorts of noises around 1 am every single night. Clattering dishes, walking around, loud talking even though he can’t be alone since his apartment feels empty. I know it sounds petty, but I need those few hours before dawn to wrap up my work for the day without interruptions from real life. But there’s no way to ignore this guy who just seems to love being a night owl. So one night when things were really quiet in my building and he hadn’t started his routine yet, I put together some makeshift soundproofing with cardboard and tape. It was probably too obvious because the next day he came over and asked what that weird setup on my wall was. I told him it’s just some new art project to liven up the place, but he clearly didn’t buy it since he looked around for a while before leaving. And now every time there's noise from his apartment, all I can think about is whether he remembers this little lie and how annoyed he might be with me. Anyway, that’s my story, hope my makeshift wall works better than my diplomacy skills did.