bless you?

When someone around you sneezes, do you follow up with the traditional, "bless you"? For some reason when no one says 'bless you' after I sneeze, during a quiet exam for example, it really makes me angry. Maybe I see it as inconsiderate, or I'm just weird. Well I was driving the other day, stopped at light, when I let out a loud sneeze! Windows up no one heard but I happen to turn to the guy next to me in a white van and I see him mouth to me, "bless you". Kind of creepy but at the same time I guess we both share the inability to ignore a sneeze.