Doctor Who season 10 episode 2 (or series 10 installment 2, if you prefer the UK nomenclature), Smile: in one scene, a smiley-robot (or Vardy interface) puts out some food for The Doctor and Bill. The interesting part is that it puts two blue cubes on one plate, but only one blue cube on the other. Bill initially suspects the future is still sexist, but The Doctor surmises that the robot has been confused by his two hearts.
The problem is, that's not the first interaction between the robots and the Doctor. A few scenes beforehand, they're handed little smiley-badges, and they each get just one. If the Doctor's two heartbeats make him "count twice", then shouldn't he have been issued two smiley badges?
And for that matter, why are there only two plates? Clearly, the robots are counting people, not heartbeats. So why the unequal distribution of food cubes?