[The Doctor stops to think and consider. Thinking about himself. Back to his first face. That didn't' travel with humans. Then didn't want Barba and Ian to go. At the end of that, that face learned that The Doctor enjoys traveling with humans. Enjoys their company.

And of course; allowed The Doctor to feel all these feelings in this regeneration. Rose taught his former incarnation that. Humans have shaped The Doctor's personality. However, he still can't understand how being around humans would change your hormones.]

Yeah, sowwy. 'Friad, I don't understand.