Curse you, Red Baron!

It happens dozens of times every day.
Person one sneezes: "Ah-choo!"
at me?
no, at you.
Person two (and 3, 4,5 if present) says, "Bless You".
So....if we are blessed when we sneezed, are we cursed when we don't? At any given moment, if noone is saying "Bless you" and that statement must be verbalized on occasions it is true...are they not in effect the rest of the time saying, "Curse you"?
No wonder we are so angry all the time.
Ah-choo!