" I said we’re not the same. Here’s why. All my life, every day, I’ve wished I was someone else. I’ve wanted to be Kate, or Sarah Jane Smith, or Amy Pond, or anyone really. But you’re a shape-shifter, you’ve been lots of other people—and you want to be me. I think that makes you a much better Petronella Osgood than I am. I think I’d like to be a better version. If "

― Steven Moffat , Doctor Who: The Day of the Doctor