One that came to mind was the "I'm shocked that gambling is going on here / Your winnings, sir" sequence, but then that's supposed to be funny.
Another that came to mind was Greenstreet and Bogart's "flirting" look exchange.
Or the scene where Lorre is talking to Bogart, starting with Lorre's "When you first came to Casablanca..." through his expressions just after Bogart walks away from him.
Gadfly