Time

Time is an important aspect of human/ faerie relations. The length of time one spends in faerie land may be different from the amount of time that passes in the human world.

For example, one could go into the fairy realm for just a few minutes, but when they come out again a hundred years have passed in the human world. An example of this is the story of Rip Van Winkle, the man who 'fell asleep' played 9 pins with some weird guys, and woke up an old man. You can read it here.

http://www.ibiblio.org/ebooks/Irving/Winkle/Irving_Winkle.pdf

On the other side of the spectrum, one could venture into the fairy realm and spend years and years there, but when they return to the human world no more than a few minutes have passed. An example of this can be found in the Chronicles of Narnia by C.S. Lewis.

There's really no saying which of the two is more common, and indeed there are many instances where there is no time issue at all. One of the weirder aspects of faerie. Maybe Santa Claus can tied into this somehow.....

Image from http://thepequodblog.blogspot.com/