Because the traveling is starting to feel like running away.

Amy

Brian: What happened to the other people who traveled with you?
The Doctor: Some left me, some got left behind and some, not many but some, died.

The Doctor is God knows where. Did real life just get started?

Rory

Within three hours the cubes had separate Twitter accounts.

Kay Stewart

Look at you now, all grown up.

The Doctor

Frightened people. Give me a Dalek any day.

The Doctor

You're both good men. You just forget it sometimes.

Isaac

Today I honor the victim's first. His, the Masters, the Daleks, all the people who died because of MY mercy.

The Doctor

Yes, I wear a Stetson now.

The Doctor

Tea, but the strong stuff. Leave the bag in.

The Doctor

So, human sleeping potion or human innuendo. Take your pick.

Amy

I'm a Sagittarius. Probably.

The Doctor

Doctor Who Season 7 Quotes

You're going to fire me at a planet? That's your plan? You're going to fire me at a planet and expect me to fix it?

Doctor Who

I made you a souffle, but it was too beautiful to live.

Oswin