Fourth Doctor: You know, the very powerful and the very stupid have one thing in common: they don't alter their views to fit the facts; they alter the facts to fit their views.

I travelled across the world. From the ruins of New York, to the fusion mills of China, right across the radiation pits of Europe. And everywhere I went I saw people just like you, living as slaves! But if Martha Jones became a legend then that's wrong, because my name isn't important. There's someone else. The man who sent me out there, the man who told me to walk the Earth. And his name is The Doctor. He has saved your lives so many times and you never even knew he was there. He never stops. He never stays. He never asks to be thanked. But I've seen him, I know him... I love him... And I know what he can do. - Martha Jones

He's like fire and ice and rage. He's like the night, and the storm in the heart of the sun. He's ancient and forever. He burns at the center of time and he can see the turn of the universe. And... he's wonderful. - Tim Latimer

Geronimo!

You don't want to take over the universe. You wouldn't know what to do with it beyond shout at it.

Angel Bob: Doctor? Excuse me, hello, Doctor? Angel Bob here, sir.
The Doctor: Ah, there you are, Angel Bob. How's life? Sorry, bad subject.
Angel Bob: The Angels are wondering what you hope to achieve.
The Doctor: Achieve? We're not achieving anything. We're just hanging, it's nice in here: consoles; comfy chairs; a forest... how's things with you?
Angel Bob: The Angels are feasting, sir. Soon we will be able to absorb enough power to consume this vessel, this world, and all the stars and worlds beyond.
The Doctor: Yeah, but we've got comfy chairs. Did I mention?
Angel Bob: We have no need for comfy chairs.
The Doctor: [amused] I made him say 'comfy chairs'.