7. Listen's Time Loop
The recently Hugo Award nominated Listen caused a lot of controversy when it first aired. It was the first time that viewers got to see the Doctor as a child. While a lot of people were blown away by the twist, a number of fans were disappointed that the Doctor's childhood was even visited at all. They felt it took away from the mystery of the character who they've known practically nothing about since his televisual inception in 1963. While the scenes in the Doctor's past were left deliberately ambiguous, viewers did learn a lot about the Doctor's childhood. They saw the importance of the barn from The Day of the Doctor and got an insight into the Doctor's options as a youth. He could have joined an army but instead he trained to be a Time Lord. Furthermore, the Doctor was also a lonely figure as a child, choosing to sleep in a barn away from the other children. However, it wasn't just seeing the Doctor's childhood that caused controversy amidst the fevered fanbase. Clara ends up comforting the young Doctor with his own words, implying that she'd given him his life motto and annoying some who felt this made her more important than any other companion in the history of the show. However, she'd gotten those words from 12, so it ended up being the Doctor giving himself part of his ideology via a good old fashioned time loop. And still creating rather a large moment in the character's backstory along the way. Only in Doctor Who, eh?