It's perhaps less relevant now that a lot of people can roll out of bed and start their remote job in sweatpants, but it's stuck with me.
(Despite being solidly white collar, I still shower of a night)
The majority of Americans I know shower in the morning. Japanese bath/shower at night as a general rule. A western person I know married to a Japanese person said their partner thought they were gross to climb into bed all dirty (not bathing at night). My friend thought "waking up sticky from sleep and staying sticky all day is gross". My friend's solution was to bath both in the morning and at night. Their partner still only baths at night.