I remember a time in a class on a cold winter morning a Japanese girl came with a surgical mask & I thought “wow people would go to extremes NOT to get sick in Japan” afterwards on a break I approached her & asked in a cynical manner: why the mask? Are you afraid of catching a cold? & then she said “in Japan you use it when YOU are under the weather & you don’t want other people to get sick, it is the polite thing to do” wow! that's a lesson I will never forget