10 Doctor Who Mysteries With The Worst Possible Answers
9. Why This Face?
When Peter Capaldi was cast as the Twelfth Doctor, everyone was adamant that the show should acknowledge why he looked like Caecilius from The Fires of Pompeii.
They were in luck, because Steven Moffat agreed with them and promised that answers would come. He first hints at this in Deep Breath, when the Twelfth Doctor ponders who frowned him that face, alongside a rather bewildered onlooker.
Skip ahead to The Girl Who Died and the answer was provided in full, but it all felt a bit underwhelming. After Ashildr dies from the strain of using the Mire helmet, the Twelfth Doctor is angry and guilty, and that's when it hits him – he chose the face of Caecilius because it reminded him to always try and save people.
But hang on... isn't that what the Doctor does anyway? At the time he chose this face he'd just spent centuries defending the people of Christmas from all manner of evil invaders. Surely he could just remember that if he was ever in doubt about his purpose?
And anyway, it wasn't Caecilius who convinced him to save his family, it was Donna. So why didn't he choose her face? Now that would've been a plot twist!