(I was originally going to post this as a response to another thread, but since my reply is so involved, I figure I ought to give it a thread of its own.)
A lot of people here don't like It's a Wonderful Life because of its religious overtones and its "Norman Rockwell" small town atmosphere (that doesn't include minorities too much, I may add).
However, when you dig into the story, you'll see a lot of subtle messages that resonate with New Deal policies of the time. The theme of the whole film is, "If everybody sticks together and helps each other out, we'll make it through." The main character, George Bailey, spends his whole life sacrificing for others, and at the end we find he's instilled this attitude in nearly everyone in the town, and they come together to help him out in his time of need.
Contrast that with Potter, the villain, who is the embodiment of selfishness and greed. It's no accident that Potter is cast as an old man, for he symbolizes a bygone era (Hoover). In the scene where Bedford Falls has been taken over by Potter and re-named "Potterville," we see the results of "every man for himself": massive corruption, widespread unemployment, vice, and civil unrest. It's a world where George's wife becomes a spinster librarian; pure, yes, but very unhappy.
The scene that I think shows these themes most vividly is during the run on George's building & loan. (Doesn’t some of this seem eerily familiar to what’s happening these days?) Notice that (except maybe for Tom) George inspires this “stick-together” attitude in the crowd, and also how much George trusts his customers.
GEORGE: Why didn't you call me?
UNCLE BILLY: I just did, but they said you left. This is a pickle, George, this is a pickle.
GEORGE: All right now, what happened? How did it start?
UNCLE BILLY: How does anything like this ever start? All I know is the bank called our loan.
GEORGE: When?
UNCLE BILLY: About an hour ago. I had to hand over all our cash.
GEORGE: All of it?
UNCLE BILLY: Every cent of it, and it still was less than we owe.
GEORGE: Holy mackerel!
UNCLE BILLY: And then I got scared, George, and closed the doors. I . . . I . . . I . . .
GEORGE: The whole town's gone crazy.
The telephone rings. Uncle Billy picks it up.
UNCLE BILLY: Yes, hello? George . . . it's Potter.
GEORGE: Hello?
POTTER: George, there is a rumor around town that you've closed your doors. Is that true? Oh, well, I'm very glad to hear that . . . George, are you all right? Do you need any police?
GEORGE (on phone): Police? What for?
POTTER: Well, mobs get pretty ugly sometimes, you know. George, I'm going all out to help in this crisis. I've just guaranteed the bank sufficient funds to meet their needs. They'll close up for a week, and then reopen.
GEORGE (to Uncle Billy): He just took over the bank.
POTTER: I may lose a fortune, but I'm willing to guarantee your people too. Just tell them to bring
their shares over here and I will pay them fifty cents on the dollar.
GEORGE (furiously): Aw, you never miss a trick, do you, Potter? Well, you're going to miss this one.
George bangs the receiver down and turns to meet Uncle Billy's anxious look.
POTTER: If you close your doors before six P.M. you will never reopen.
He realizes George has hung up, and clicks the phone furiously.
An ominous SOUND of angry voices comes from the other room. George and Uncle Billy exit from George's office. More people have crowded around the counter. Their muttering stops and they stand silent and grim. There is panic in their faces.
GEORGE: Now, just remember that this thing isn't as black as it appears. I have some news for you, folks. I've just talked to old man Potter, and he's guaranteed cash payments at the bank. The bank's going to reopen next week.
ED: But, George, I got my money here.
CHARLIE: Did he guarantee this place?
GEORGE: Well, no, Charlie. I didn't even ask him. We don't need Potter over here.
CHARLIE: I'll take mine now.
GEORGE: No, but you . . . you . . . you're thinking of this place all wrong. As if I had the money
back in a safe. The money's not here. Your money's in Joe's house . . .
(to one of the men) . . . right next to yours. And in the Kennedy house, and Mrs. Macklin's house, and a hundred others. Why, you're lending them the money to build, and then, they're
going to pay it back to you as best they can. Now what are you going to do? Foreclose on them?
TOM: I got two hundred and forty-two dollars in here, and two hundred and forty-two dollars isn't
going to break anybody.
GEORGE (handing him a slip): Okay, Tom. All right. Here you are. You sign this. You'll get your money in sixty days.
TOM: Sixty days?
GEORGE: Well, now that's what you agreed to when you bought your shares.
There is a commotion at the outer doors. A man (Randall) comes in and makes his way up to Tom.
RANDALL: Tom . . . Tom, did you get your money?
TOM: No.
RANDALL: Well, I did. Old man Potter'll pay fifty cents on the dollar for every share you got.
(shows bills)
CROWD (ad lib): Fifty cents on the dollar!
RANDALL: Yes, cash!
TOM (to George): Well, what do you say?
GEORGE: Now, Tom, you have to stick to your original agreement. Now give us sixty days on this.
TOM (turning to Randall): Okay, Randall.
He starts out.
MRS. THOMPSON: Are you going to go to Potter's?
TOM: Better to get half than nothing.
GEORGE: Tom! Tom! Randall! Now wait . . . now listen . . . now listen to me. I beg of you not to do this thing. If Potter gets hold of this Building and Loan there'll never be another decent house built in this town. He's already got charge of the bank. He's got the bus line. He's got the department stores. And now he's after us. Why? Well, it's very simple. Because we're cutting in on his business, that's why. And because he wants to keep you living in his slums and paying the kind of rent he decides. Joe, you lived in one of his houses, didn't you? Well, have you forgotten? Have you forgotten what he charged you for that broken-down shack? (to Ed) Here, Ed. You know, you remember last year when things weren't going so well, and you couldn't make your payments. You didn't lose your house, did you? Do you think Potter would have let you keep it? (turns to address the room again) Can't you understand what's happening here? Don't you see what's happening? Potter isn't selling. Potter's buying! And why? Because we're panicky and he's not. That's why. He's picking up some bargains. Now, we can get through this thing all right. We've got to stick together, though. We've got to have faith in each other.
MRS. THOMPSON: But my husband hasn't worked in over a year, and I need money.
WOMAN: How am I going to live until the bank opens?
MAN: I got doctor bills to pay.
MAN: I need cash.
MAN: Can't feed my kids on faith.
During this scene Mary has come up behind the counter. Suddenly, as the people once more start moving toward the door, she holds up a roll of bills and calls out:
MARY: How much do you need?
George jumps over the counter and takes the money from Mary.
GEORGE: Hey! I got two thousand dollars! Here's two thousand dollars. This'll tide us over until the bank reopen. (to Tom) All right, Tom, how much do you need?
TOM (doggedly): Two hundred and forty-two dollars!
GEORGE (pleading): Aw, Tom, just enough to tide you over till the bank reopens.
TOM: I'll take two hundred and forty-two dollars.
George starts rapidly to count out the money. Tom throws his passbook on the counter.
GEORGE: There you are.
TOM: That'll close my account.
GEORGE: Your account's still here. That's a loan.
Mary turns and slips out through the crowd, followed by Ernie. George hands the two hundred and forty-two dollars to Tom, and speaks to Ed, the next in line.
GEORGE (cont'd): Okay. All right, Ed?
ED: I got three hundred dollars here, George.
Uncle Billy takes out his wallet and takes out all the cash he's got.
GEORGE: Aw, now, Ed . . . what'll it take till the bank reopens? What do you need?
ED: Well, I suppose twenty dollars.
GEORGE: Twenty dollars. Now you're talking. Fine. Thanks, Ed.
(to Mrs. Thompson, next in line) All right, now, Mrs. Thompson. How much do you want?
MRS. THOMPSON: But it's your own money, George.
GEORGE: Never mind about that. How much do you want?
MRS. THOMPSON: I can get along with twenty, all right.
GEORGE (counting it out): Twenty dollars.
MRS. THOMPSON: And I'll sign a paper.
GEORGE: You don't have to sign anything. I know you'll pay it back when you can. That's okay.
(to woman next in line) All right, Mrs. Davis.
MRS. DAVIS: Could I have seventeen-fifty?
GEORGE: Seven . . . (he kisses her) Bless your heart, Of course you can have it. You got fifty cents? (counting) Seven . . .