LAST EDITED ON 01-18-13 AT 06:16 PM (EST)

Most of these quotes are great because they evoke memories of a particular scene. One that I love that has a great scene connected with it but also stands on its own merits is:

"I'm as mad as hell, and I'm not going to take this any more!"

But for bringing back memories of a scene, there probably isn't a better quote than "Round up the usual suspects."

The real love story in Casablanca isn't Rick and Ilsa or Victor and Ilsa; it's between Captain Renault, who is, after all, "only a poor corrupt official" (in his own words), and the audience. The audience wants to like Renault, who (clearly against his will) has to dance to the Gestapo's tune while getting off the best lines in the movie, like these in addition to the "gambling" one referenced earlier:

Major Strasser: You give <Rick> credit for too much cleverness. My impression was that he's just another blundering American.
Captain Renault: We musn't underestimate "American blundering". I was with them when they "blundered" into Berlin in 1918.

Captain Renault: Rick, there are many exit visas sold in this café, but we know that you've never sold one. That is the reason we permit you to remain open.
Rick: Oh? I thought it was because I let you win at roulette.
Captain Renault: That is another reason.

Major Strasser: What is your nationality?
Rick: I'm a drunkard.
Captain Renault: That makes Rick a citizen of the world.

Captain Renault: Ricky, I'm going to miss you. Apparently you're the only one in Casablanca with less scruples than I.

Captain Renault: Have you lost your mind?
Rick: I have. Sit down!
Captain Renault: Put that gun down!
Rick: I don't want to shoot you, but I will if you take one more step!
Captain Renault: Under the circumstances I will sit down.

Rick: And remember, this gun is pointed right at your heart.
Captain Renault: That is my least vulnerable spot.

Yet we know Renault is a bad guy. We saw him try to force the poor Bulgarian woman (Annina) to sleep with him in return for exit visas for herself and her husband -- an act that made Rick so disgusted that he used the rigged roulette wheel to give her (and her husband) the money to buy their way out legitimately. He was also behind Ugarte's death (to show off to the Gestapo) and then joked about it:

Captain Renault: I am making out the report now. We haven't quite decided yet whether he committed suicide or died trying to escape.

And yet, in the movie's last sequence, Renault totally redeems himself and pays off the audience for liking him despite all of his actions earlier in the movie, by covering for Rick's murder of Major Strasser. Honestly, in my opinion it's the one thing that sets Casablanca apart from all of the other contenders for all-time best picture -- none of the other pictures has a believable last-scene redemption. But Casablanca does. Viva la France!

The funny thing about that ending is that it was totally unplanned. The original ending (which always had Ilsa leaving with Lazslo, because the Hays Code prohibited showing a woman leaving her husband for her lover) had Rick arrested as the plane flew away overhead, but no one liked it. Because the original script had been such a mess (for example, the writers never fixed the mistake in the script that had the letters of transit signed by Free French Gen. DeGaulle instead of by Vichy Gen. Weygand), the film was shot in sequence to permit re-writes at the end. And the rehabilitation of Renault was possible only because of that.