Update, Dec. 1, 2012: I've identified even more why I don't like it. See paragraphs at bottom.
A few years ago, I wrote a fairly long blog post about the Frank Capra/Jimmy Stewart chestnut possibly needing a remake, as well as some things that were wrong about this saccharine bit of of sentimentality, and extensively updated it last year at Christmas time. The post incorporated a couple of other bloggers' takes on issues or problems with the movie, which I didn't fully tackle at the time.
Well, now I am.
First, it's not just sentimental, it's, as I said above, saccharine about it. And cheesy. "Fiddler on the Roof," arguably, is sentimental, albeit darkly so. "The Sound of Music" is also sentimental, and overall, sunnily so, while accepting (as based on a true story) that Austria was dead (even as it mythologized Austria). But, "It's a Wonderful Life" has no nuance.
Second, in the actual movie, what's to be so sentimental about? Sure, George Bailey has all these friends helping him out. In fact, he's not only recouped the money Uncle Billy lost, but much more. Beyond that, even a George Bailey as soft-hearted as Capra's would have, at a suitable point in the next year, quietly but firmly pushed Uncle Billy on part-time status while looking for a permanent replacement.
Related to that, after the end of World War II, Bedford Falls would have gotten its own housing boom, even its own small Levittown. Most buyers would have taken loans from Bailey, not Potter. George Bailey might have come into decent money. Or, he might even have gotten rich.
Third, Capra HUGELY stacks the deck with his Clarence.
Clarence shows everything that went wrong by George never being born, but he never shows everything that went RIGHT by George never being born. Indeed, he and Capra never even offer that as a possibility, that some people might have been better off had George Bailey never been born.
It's like people who believe in reincarnation, but "somehow" always remember being a king in a past life, but never the person shoveling the shit out of the king's stables, let alone a dung bettle rolling around in that shit.
Maybe if George hadn't been born, Potter would have taken over the building and loan, then had a massive coronary a month later from overwork. In that case, somebody almost as nice as George Bailey might have replaced both him AND Potter.
(Per a 1992 bio of Capra, one director has another idea: George should have actually committed suicide. I could buy into that angle, too.)
So, I'm tired of crying sappy saccharine tears of this movie, and over how it makes me recognize my own life hasn't turned out so well in some ways. If I ever see it again in the next few years, I hope I get angry instead.
Update, Dec. 1, 2012: I watched bits and pieces of the whole thing, and all of the last half hour. I had to steel myself once or twice, but didn't come close to a real lump in the throat, let alone more.
And, I recognize even more why I don't like the movie ... it's along the "reincarnation" lines, but even blunter.
It's like when pro-life people say, "Would you have aborted 'Baby X' with a bad childhood? Congratulations. You aborted Leonardo, or Beethoven, or whomever." But pro-choice people can respond with similar counterscenarios, and say, "Congratulations. You kept Hitler alive to perpetuate the Holocaust."
It's that kind of deck-stacking that Capra does.