"Achoo" - "God Bless you"
Ever wonder why we pray for God's blessing after someone sneezes? It comes from an ancient belief that a person's breath was the same as their soul. When God made Adam, He breathed life into him. Thus, a myth grew up around this belief that a sneeze was thought to rapidly send the life of a person out of them.
When this life leaves, a vacuum is left which could be filled by evil spirits.
Then, during the reign of Pope St. Gregory the Great, there was a plague in the area. Thus, Gregory instituted the phrase "God bless you" as a way to ask for divine protection if one were to become sick or die.
Then there is Yawning. Why do you cover your mouth when you yawn?
Some modern moms say it is because it is rude to yawn in front of others. While our culture may reflect this as the modern reason, it has a much more ancient origin.
Some French and English taught that yawning was another opportunity for the devil to enter, thus you covered your mouth to bar his entrance. In Ireland, they would make the sign of the cross over their mouths while yawning. Still today, some Muslims believe this can happen when one yawns.
Now you know that some of our common practices come from myths and legends.