Perhaps the cultural phenomenon is that in Japan it is considered far more impolite and socially unacceptable to complain about smacking and slurping noises regardless of one’s own distress than it is to make those noises in the first place.
I dated someone once who used to like to eat cereal in bed, and I thought I was crazy because the sound of it in an otherwise quiet room made me incredibly stressed out and angry, but in thinking that I also was far too mortified to complain about it. Only years later did I discover that other people had the same experience.
