Eleven: Hey. Look. The round things!
Ten: I love the round things.
Eleven: What are the round things?
Ten: No idea.
(“The Day of the Doctor”)

Clara: You’ve redecorated.
Twelve: Yes.
Clara: I don’t like it.
Twelve: I’m not entirely convinced myself. I think there should be more round things on the walls. I used to have a lot of round things. I wonder where I put them.
(“Deep Breath”)

Clearly, Thirteen's problem was insufficient roundel nostalgia.

#DoctorWho