If Santa actually visited every house in 1 day...
Santa takes a fraction of a millisecond to land on your rooftop, scoot down the chimney, put presents under the tree, fill up the stockings, eat the snacks, zip back up the chimney, cleanup any reindeer droppings on the roof and take off for the next house. That's hustle!
A skeptic might argue that even though Christmas is celebrated in 149 countries, those that do may be in the minority and in many cases, Santa is not a part of their Christmas tradition. True. But, if we consider how much work Santa must do in just North America where the many do include Santa Claus in their holiday traditions, we can calculate that Santa must spend 1.25 milliseconds per visit. Now matter how you cut it, Santa is one fast dude.
To give you an idea of how fast this is, let's imagine that our Christmas tree is 50 feet from the rooftop. If we use the conservative North American estimate (1.25 milliseconds/visit), then Santa is traveling through the house about 55,000 miles per hour. Or, if Santa were to spend one minute per house, it would take him approximately 65.6 years to complete his rounds. It's certainly no wonder that Santa is portrayed as a jolly "old" fellow; it could take him nearly a lifetime to make one delivery.
So why I haven't I seen Santa? I blinked. According to Professor Craig Evinger from the State University of New York at Stony Brook, a blink lasts approximately 200 milliseconds. This means that your average blink takes 160 times longer than it takes Santa to visit your home. Or from another perspective, in the time it takes you to blink just once, Santa has already filled the stockings at your house and 159 of your neighbors. So if you, like me, have ever blinked on Christmas Eve, chances are you missed Santa - he came and left in the twinkling of our eye.