What I like about [Berthold] Brecht, it's very interesting. When Helene Weigel came over and somebody talked about Lotte Lenya and said "well, she wasn't alienating." And Weigel said "No, no, no. Why, Lotte Lenya was so true - who cares?" She said: "Berti only developed the theory of alienation in order to stop bad acting." I heard her say that. Now that's brilliant.

By the time I came to do the final ones [Harry Potter's film], I was working on something that was massively successful. There was a huge difference in indulgence and all sorts of stuff. A very big difference in peoples' attitudes. They were very pleased with themselves. In human terms, it was quite interesting to see the difference.

What I like about [Berthold] Brecht, it's very interesting. When Helene Weigel came over and somebody talked about Lotte Lenya and said "well, she wasn't alienating." And Weigel said "No, no, no. Why, Lotte Lenya was so true - who cares?" She said: "Berti only developed the theory of alienation in order to stop bad acting." I heard her say that. Now that's brilliant.

It's quite interesting, looking back at the first one [film about Harry Potter], nobody knew whether or not it was going to be successful as a film. The books were of course already very successful, but that's happened before, where the books were successful and the films weren't at all. But it turned out that they were.

The big problem with literature is people tend to take the dialogue from the book, forgetting that everything that surrounds it is literate, therefore not knowing quite how to put that on screen.

A mathematician either has a feeling for equations and an understanding and delight in it, not only in the purity of it, but in its beauty as well. I don't think that's something that you learn at school. I think you can get better in mathematics on a school level, but when you're talking about being a mathematician, I think that's definitely a gift of genes or whatever, you know? Whatever your pool is.

Bong Joon-ho is enormously sensitive to performance. He knows what he needs to see and that's all he needs to shoot. He is so daring. We don't do that in the west. We shoot everything.