Like a lot of Japanese girls, I'm a bit obsessed with personal hygiene. Sometimes I get up 2AM to have a shower... after already having one before going to sleep, because something just doesn't feel "right".
And I work in a more diverse corporate environment where we have people coming and going from Korea and Hong Kong all the time. One thing I notice is that I catch flu quite easily, at almost every single turn of a season. Just recently I caught flu twice... within half a month, both recovered well within 3 days with minor complications remained like running nose or cough.
At the same time, I notice that colleagues and ex-college friends who are about the same height, age and weight as me but doesn't pay much attention to personal hygiene rarely get sick...
I understand the whole thing could just be a confirmation bias. But I still want to know, is there any scientific studies done which shows that being super "clean" actually "spoil" or "overly-pamper" your immune system?