While watching Michael Mann's Heat, I discovered the "cup of coffee test" for screen villains. I found myself thinking again of that great scene in which the cop (Al Pacino) and the villain (Robert De Niro) sat down to share a cup of coffee. It was a simple gesture, with no chasing or guns or shooting. Just talking. But it demonstrated on a thematic and visual level that this hero and this villain were actually very close to one another. They were very similar people, with similar natures.
I started applying this test to almost every movie. Not surprisingly, most of them fall apart. Most movie villains simply sneer and cackle and try to take over the world. But think of Batman and the Joker in The Dark Knight. They don't literally have coffee together, but they do sit down together for a talk; the movie presents them as equals, and separate from the rest of the world. They understand one another better than anyone else. Consider, also, Col. Landa (Christoph Waltz) in Inglourious Basterds, who sits down several times with several heroes over several different kinds of beverages (ranging from milk to wine). He's snaky, but smart and always cordial.
Sometimes the rule gets a little gray. For example, Clint Eastwood and John Malkovich don't exactly stop for coffee in In the Line of Fire, but they do have a quick, revealing phone conversation in which it is established that they are kindred spirits. And it's unlikely that Clarice Starling would sit down for coffee with Hannibal Lecter in The Silence of the Lambs -- mainly because he would probably use it to kill her -- but they do sit down and talk together.
And then, sometimes, all it takes to be a cool villain is a black mask and a respiratory problem. What do you think, dear readers? Do your favorite villains pass the "cup of coffee" test?