The story of Sherlock Holmes, on the surface, is about detection, but in reality, it's about the best of two men who save each other - a lost, washed-up war hero and a man who could end up committing murders instead of solving them. They come together. They become this perfect unit. They become the best friendship ever, and they become heroes. That's what we fall in love with, not Sherlock on his own. No one can love that man on his own, but Sherlock Holmes and Dr. Watson - the best friends ever.

I don't think, generally speaking, people become writers because they were the really good, really cool, attractive kid in class. I'll be honest. This is our revenge for people who were much better looking and more popular than us. I was a bit like that, I suppose.

Nothing can ever be a rule in drama, because then you're saying certain things won't ever happen, and that would be very boring.

Hitler: Thank you, whoever you are. I think you just saved my life. The Doctor: Believe me... It was an accident.

The trouble with a series as it gets older is it can feel like a tradition, and tradition is the enemy of suspense, and it's the enemy of comedy. It's the enemy of everything, really. So you have to shake it up.

An awful lot of storytelling isn't really about making people understand - it's about making people care.

All lives end. All hearts are broken. Caring is not an advantage.