The Doctor: Oh, now what's this, then? I love this. A big, flashy-lighty thing. That's what brought me here. Big, flashy-lighty things have got me written all over them. Not actually, but give me time... and a crayon.

Never ignore a coincidence. Unless you're busy, in which case, always ignore a coincidence.

I'll be a story in your head. But that's OK. We're all stories, in the end. Just make it a good one, eh? Because it was, you know; it was the best.

Never knowingly be serious. Rule 27.

What's the point of being a grown-up if you don't get to be immature?

We're thrilled to have Maisie Williams joining us on Doctor Who. It's not possible to say too much about who or what she's playing, but she is going to challenge the Doctor in very unexpected ways. This time he might just be out of his depth, and we know Maisie is going to give him exactly the right sort of hell.

Witty and mean is easy - but fond and funny is hard.