When I was in America, my friends said to me "Bless you!" if I sneesed.
But in Japan, we say nothing if anybody sneesed.
I feel lonly when I sneeze here...
Because my hometown Okinawa has almost same culture with "Bless you!" for sneezing!
We say "くすけーひゃー！" for somebody's sneezing.
So, I just say "くすけーひゃー" for myself, after I lest Okinawa.