When a young woman refugee in Casablanca pleads for Rick's help with finances, her talk about her love for her husband convinces Rick to get his roulette croupier to rig the game for one win and enough money for the couple to buy their way to safety in America.
And when Rick's staff (made up of exiles and refugees like himself) find out, they all hug and kiss him for his humane act.
While not as iconic as Rick's sacrifice mentioned above, Viktor gets a similar one just a few scenes earlier when he tells Rick to get Ilsa out of Casablanca and keep her safe, even at the cost of losing his own opportunity to leave. "Apparently you think of me only as the leader of a cause. Well, I'm also a human being. Yes, I love her that much."