The difference between a beautifully made failure and a beautifully made hit is who you've got playing the leads.

I write the kind of stuff I'd like to watch.

Amy Pond: 'I thought... well, I started to think you were just a madman with a box.' The Doctor: 'Amy Pond, there's something you better understand about me, 'cause it's important and one day your life may depend on it. [He Smiles] I am definitely a madman with a box.

You should always waste time when you don't have any. Time is not the boss of you. Rule 408.

I never go online. The Internet stuff is bonkers. You must not look at it.

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.

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.