To Have and Have Not established the team of Bogie and Bacall. Lauren Bacall was cast for the role when she was a 19-year-old model. Humphrey Bogart was a 45-year-old established star. And yet, they sold the relationship. Bacall was the only woman tough enough to match Bogart without sacrificing any of her 1940's class. The film plays to both actors' strengths. Like in Casablanca, Bogart is the rough-around-the-edges good guy who you might mistake for a bad guy at first. He's an American who takes on a role perfected by Kipling and other British imperial writers. He's been accepted into the foreign culture -- and sort of seems to run things. But then, the war interferes with his exotic, yet comfortable life.
Bacall carries herself like a beautiful woman who knows she's beautiful, and has never really had to prove it. She accepts her looks as a simple matter of fact. When she meets her equal, they play and tease - even though they realize as clearly as the audience does exactly what is going on.