Santa Theory
Everyone says the Santa from the beginning of the movie was killed. While I perfectly understand where they're coming from, I personally don't believe it. Here's what I think:
A long time ago, he became Santa the same way Scott does throughout the course of the movie. When he fell off the roof and disappeared, that was him returning to his original life. One more thing, I know this might be irrelevant, but that Santa couldn't have been that nice of a guy because notice how excited the elves were that there was a new Santa, and in the second movie, somebody (I don't remember who) said that the kids were 80% happier since Scott took over.
Thoughts are perfectly welcome.