That's exactly it. You watch these old films and they never patronise you. They are always multi-layered and expect you to work these things out for yourself. Nowadays, most cinema seems to like hitting you over the head with a blunt instrument.

I adored Lorre in Casablanca, though I think I liked everyone in that film. I like that he didn't shy away from playing such a character in M and even managed to give someone like that a certain vulnerability. I felt I should hate the character, but my heart was in my mouth when the criminals were searching for him.

Are there any silent films you'd recommend?