Have you ever noticed the similarities betwen A Christmas Caroland It's a Wonderful Life? I mean, besides the fact that they're both set at Christmas. (That is significant, but I'll get to it in a moment.)
Both stories involve a man receiving a special visitation on Christmas Eve, and being taken back through his own past. One man sees the bad things he's done, the other the good. But both are forever changed by the journey.
Neither story is overtly religious, and yet both of them are rooted in a religious view of human nature -- and when you take them together, they comprehensively show the Christian view of that nature. The first, at its most basic level, shows us man as a sinner in need of saving; the second shows man as a creature of worth and value. And when you take into account that both their stories take them from Christmas Eve to Christmas Day, it's hard not to see in them the life-changing power of man's encounter with the divine.
Ebenezer Scrooge's nephew Fred opines that nothing belonging to Christmas can be "apart from the veneration due to its sacred name and origin." So read and watch these two stories, but view them in the context to which they belong. You'll see just how faithfully they reflect the greatest Story.