I had the worse neighbors once when I lived in an apartment building. They were this young couple, probably about my age at the time (early twenties), and they were clearly not compatible. They'd fight all the time, making the loudest noise while doing so. They'd scream and throw things, and I'd always pray they broke up because I didn't want to deal with this anymore. But then they'd make up and have loud sex, which was probably even worse. I put up with them for about a year before I decided to finally move out and let them bother another person.