Has to at least be in the conversation.
At a high level it's a good old feelgood Christmas classic. But beyond that, the subtleties and the stuff below the surface is what makes this one of the all-time greats.
It's a great example of how simple life seemed back then. And man, what a genuinely good guy George Bailey is, and how incredibly likeable he is -- and yet, in a departure from Christmas movie cheesedom, he's not perfect. Like his character would in the real world, he sometimes gets moody and surly and impatient. He gets jealous of his buddy Sam Wainright who moved away to big New York City and became a big shot. It really eats at him -- he wanted to get away, to see the world, to build things, to move to the big city, but he never got that chance. He is too proud sometimes. He is torn between his romantic view of the adventure that life should be in his head, and yet shows his interest in the material parts of life (like when he nearly accepts Mr. Potter's offer to come and work for him) and ultimately gets caught up in a girl, and a family, same as everyone. Jimmy Stewart is such a wonderful actor and just absolutely nails the part. He is George Bailey. Both at the surface, and in all of these nuances, he plays it perfectly.
And the dialogue is just wonderful and so clever. In some places it's downright funny. And despite how simple life seemed back then, there are some great almost racy nuances that remind you things really haven't changed all that much -- like when the guys and BSing in the street and Violet walks by, and they all stop and stare mouths agape, and then very subtly Bert the cop mumble rushes off to see his wife. Awesome!
Then you've got some more obvious imagery, like the crow in the scene every time things are about to go bad. What other stuff have I missed here?
All in all, just such a fantastic movie.