(Not a very good picture, but part of the idea was to keep the Central Park Rangers hidden and therefore more mysterious and ominous a force).
I appreciated his recognizing that fairy tales are actually rife with danger and scary parts, as opposed to the all-to-prevalent view that the fairy tale world is more like the North Pole of this movie, where things are so childlike and innocent that to call someone a "cotton-headed ninny muggins" is shocking. Of course, the Central Park Rangers are hardly even frightening, although the director Jon Favreau did say they were secretly an homage to the ringwraiths in Lord of the Rings.
Also: This Cinema Blend movie review of "Elf" claims that the story "borrows heavily from other well known tales (most obviously “A Christmas Carol” and “The Ugly Duckling”)", but nowhere did either Favreau or Farrell ever mention those stories, although they did discuss their inspirations and the motivations behind plot elements and changes to the script. (One of them did, at one point, compare James Caan's character to Scrooge). I think it just goes to show how powerful the classic fairy tales are, that people assume any similar story is "borrowing" material. The concept of someone who feels like they don't belong is a very universal problem; all of us at times question our identity or purpose in life. But of course, we're all familiar with Andersen's fairy tale, so we can't really prove it doesn't subconsciously influence the stories we create...