Rick's revenge on Ilsa
I'm surprised the sharp CASABLANCA fans on this board still fall for the most cynical ending in Hollywood history. Calling Rick's gesture to Ilsa and Victor Laszlo "noble" at the end of CASABLANCA, is to miss the Machiavellian ending supplied by the Epstein brothers.
To quickly re-cap: at the climax of the film, Ilsa is planning to stay with Rick in Casablanca, and send Victor to Lisbon to continue his work. The embittered Rick instead tells his beloved she must go with her husband to give him the strength he needs. So far, so good.
Here's where it gets interesting. Rick then tells the husband the whole scenario of what happened. Even though Laszlo tells Rick he doesn't need to know what went on between his wife and Rick; Rick says, "I'm going to tell you anyway." Rick then spills to Laszlo he not only had an affair with his wife in Paris, but they conjugated just the previous evening in Rick's office ... while Laszlo was downstairs!
Rick tells Laszlo, "It may make a difference later." Of course it will; Rick's planted doubts in a husband's head about his wife's fidelity. Not only that, he made his sexual encounter with Ilsa sound noble because she was doing it on Laszlo's behalf ("She did everything in her power to make me think we still had Paris. For her sake, I let her pretend"). Laszlo clearly is a man who didn't want to know the details, as he also told Ilsa in the hotel scene earlier in the film. At the airport, Rick needlessly fills in those details that will have Laszlo wondering for years after what might happen then next time he leaves his wife in a "lonely" situation like he did in France. That look Laszlo gives Ilsa as they walk towards the plane is one of doubt, Laszlo's thinking, who is this woman and can I ever trust her again? All under the scheming, watchful eye of Rick Blaine.