It's A Thing: Last Christmas

Tangerine Dream. I'm so sorry.

Moffat-Era Tropes: Mildly embarrassing revelations about characters' childhoods. Timey-wimey. Variants on the phrase “timey-wimey” (here, “beardy-weardy” and “dreamy-weamy”). People living in virtual worlds or dreams and being unaware of this fact. Doctor leaves companion and returns when she's an old woman (seriously, that hideous old-person makeup was possibly the worst thing about this episode). “Don't blink” (in this case, close your eyes and don't think about the sleepers). Zombified people marching about until being ordered to go back to bed (see “The Doctor Dances” for the prototype version). Meeting a mythological figure who can't possibly exist. Significant messages appearing on a blackboard or wall. Scottish jokes. References to classic Christmas stories (e.g. “God bless us every one,” or the visual of people soaring over a festive London). MILF. Things coming out of TV screens at people. Referring to a companion's husband by the companion's name (“is there a Mr Clara?”).

It's not a trope, but mad props for including a visual reference to Cocteau's avant-garde film Orphee (Clara standing still as the background recedes behind her, which happens in Cocteau's film when characters journey through the underworld).

A Thing in a Thing: A dream in a dream in a dream in a dream in a dream.....

The Doctor is A: Dream.

The Master Is A: Dream.

Clara Lies About: In a totally foreseen development, Clara and the Doctor find out that they lied to each other last episode.

Reasons Clara Should Drop Danny Like A Hot Potato: Because, although the dream-Danny we meet is a complete gent, he is, as he himself points out, dead, and not going to come back.

Child Count: One (briefly).

The Thick of It: Didn't spot anything, but Red Dwarf would like a word.

It's Actually About: The tangerine on the windowsill at the end of the episode, and the Doctor “waking up” by the volcano from “Dark Water” shortly beforehand, indicate that we're still in a dream (a tangerine dream, presumably), and the fact that Santa Claus turned up in the Tardis at the end of “Death in Heaven” indicates that we have been in a dream for some time. Therefore, a certain percentage of Doctor Who, and potentially all of it, is actually a dream. This, consequently, not only retroactively makes sense of all the daft ideas and continuity problems that have gone before, but effectively insulates the entire series against future snarking. So much for this column, then.