
When Rick met Ilsa at Casablanca, although Ilsa was still as beautiful as she was in Paris, she was not free any more. There's a guy standing beside her all the time, which is her husband, Victor. Rick couldn't move his eyes from Ilsa, but his mind was filled with anger and confusions. Later he found out that Ilsa didn't show up in the train station because her husband was found out alive and sick. Rick finally forgave Ilsa when he realized that she's still madly in love with him. At the end of the movie Rick could just put his name on the visa letter and fly to America with Ilsa, but he didn't. Instead he transfered the opportunity to Victor under the danger of sacrificing himself, only because he thought that was the best for Ilsa.
The presence of Victor to some extent generates dislikes since Rick and Ilsa looked so happy in Paris. However, Under the background of war, Victor was thrown into the Concentration camp and disappeared for a year. It was during his absence when his wife fell in love with Rick. Nobody can blame him if he chose to be bitter, but he didn't. He chose to believe Ilsa and didn't ask her any questions about Rick. This is his way to love Ilsa.
Most war movies are so tragic, however Casablanca is definitely not one of them. People are so small facing a war, but they still can manage their lives by making the right choices as what Rick and Victor did.