Previous Doctors liked humans, thought they were special and worth looking after. This Doctor seems to have some disdain for them, as if saving humanity from things they don't know about is a boring chore, like taking out the rubbish on a Thursday evening. Clara was The Impossible Girl who turns up in all sorts of places and ways and now the has been demoted to tag-along teacher.
Best bit of the episode: Tell me, or I'll smack you so hard you'll regenerate.
Worst bit of the episode: pretty much everything else.