"Bad Dog!"
"Affirmative."
And I quite enjoyed the whole Doctor-Sarah-Rose triangle. That was lovely. I've always thought that Sarah was the companion most likely to have had romantic feelings for the Doctor, so it was was both fun and poignant the way they toyed with the implications of the Doctor's relationships without ever defining what they actually were. Totally got teary at the end.
And next week's is written by Stephen Moffatt!