The tradition of hanging mistletoe goes back to the ancient druids! It was believed, mistletoe possessed mystical powers which brought good luck to the household and warded off evil spirits.
Kissing under the mistletoe started in ancient Greece, during a festival called Saturnalia and was also used during weddings.
There are many traditions throughout the times regarding this plant but the most common now days is kissing under the mistletoe over Christmas. Maybe this is the Greek tradition continuing as it is a hope for marriage?
Whatever the reason, if you get the opportunity, get ready to PUCKER UP!