3. People express gratitude.
Another reason from people saying bless you is this, people in the olden times believed that it is good luck if somebody is sneezing in your direction. So they said expressed their gratitude by asking God to bless them.
4. The Heart STOPS for a millisecond.
This is actually the most common belief that led to phrase gaining popularity. It is said that when you sneeze your heart stops for a millisecond. And people give you blessings to overcome that short lapse in your mortal life. They believe that the sneezer has overcome death and hence celebrates them coming back to life.
5. It is a polite gesture.
Okay, this one is sweet and sane at the same time. Though it does not give any demoniacal explanation (which sounds interesting!) it is the most acceptable one. Why not just bless everyone on the way! Saying bless you is definitely a good thing. And nobody likes sneezing, for obvious reasons, so someone blessing you definitely feels good!
