The Doctor shrugs. "That's because you all think your imaginations are so good. But they're pitiful. All that time wasted wondering what you'll do when the planet dies, or you get invaded, or whatever. You never dare to dream about what happens if you actually make it. What if you survive."

Which is about the most annoying thing about humans ever.

"I'll keep in mind where to find you. Good mechanics are hard to find."