[Snippets] "The thing about Clara is she thinks the show is called Clara. She really does. She has no idea she’s number two in the credits, which is why we did that joke in “Death in Heaven.” She’s got a high opinion of herself, not in a conceited way, but in a correct way. She knows she’s extremely clever and capable, and she doesn’t feel like she particularly fits in the world that she lives in. [...] When I first wrote Clara, I thought, “Oh, this is fun. If the Doctor were a young woman living in contemporary Britain, it’d be a bit like her.” [...] So, Clara’s not the Doctor; she’s not the same person as the Doctor, but - the traditional thing is to say the hero and the archenemy are mirrors of each other. Are they? Are they though? Not really. I think it’s more likely that friends are mirrors of each other. If you watch any close friendship, the extent to which they start to duplicate each other is quite interesting, even with Dr. Watson and Sherlock Holmes. While they’re different people, they have similar appetites.
So, that's my lovely theory out the window, but at least I wasn't far wrong...