4. Liar Liar, Pants On Fire
The Series 8 finale, Death in Heaven, showed Clara and the Doctor part on a lie - or two lies, to be precise. Clara told the Doctor that Danny Pink had indeed returned from the afterlife for their happily ever after while the Doctor revealed to her that he'd found Gallifrey and that he was finally heading home. It was a way for them to bid farewell to each other without having to worry about how the other would get on without them. In Last Christmas, though, both truths were revealed and for Clara not be upset that he had lied to her (even though it was in her best interest and even though she lied to
him, too) displays a friendship that is unfazed over things that can be easily dismissed in the grander scheme of things. They both realised they had been doing the right thing for each other and as such there was no repeat of what happened in Into the Dalek (below).