Lets talk about breath.
Bad breath that is.
Bad breath on the trains, bad breath in the classrooms.
Bad breath standing in line for a cheeseburger.
Bad breath while sleeping in bed.
Bad breath in the doctors office.
Bad breath everywhere.

CLOSE YOUR MOUTH WHEN BREATHING IN PUBLIC.
(Breathing through the nose gets you the same results.)

Your mouth stinks and I don't want to smell it.