I think it's quaint and somewhat endearing that you see Japanese people running around wearing surgical masks. It speaks to a certain meticulousness, paranoia, and, yes, even consideration for others. It's also the only way people ever seem capable of covering their mouths when they cough and sneeze. On the flip side though, there is an issue when they keep wearing them even when they are indoors and in a conversation with other people. In my work, it is not uncommon for people who are wearing masks to protect themselves from the swarming bacteria of crowded public spaces to keep them on while they share my tiny cubicle with me. I'm not the least bit offended that they want to protect themselves against "my germs" or those left behind by other students, but I really dislike the fact that I can't see more than half of their faces when talking. It's harder to read expressions and feels like I'm having a convivial conversation with a bank robber.
I won't miss talking to people who are wearing surgical masks.