Quick note for all of those complaining about how the MC is pretty much overthinking everything, it's far, far worse in the WN because the writer goes in
deep. The mangaka has, no joke, cut out so much of Michio's thought processes that it's not the slog to read that it is in its original form.
@Yurnero
@yldDavid
The whole bath thing is actually that much of a Big Deal for the Japanese for reasons mostly related to their state religion, Shinto. Without going too much into it because there's a lot to cover, Shintoism abhors impurity, which includes things like dirt, death (this is why funerals in Japan are Buddhist Ceremonies), and things that would "stain" something pure. Baths are a way of purifying oneself from the stains that experiencing life would bring, and the way they wash is a part of that, scrubbing off dirt before submerging themselves into soothing water. It's also not just a way to keep clean, but to also be social or a way to ease one's stress from a long day.
It's something that's pretty much carved into Japanese Culture, much like rice.