9. The Universe Was Created By Terminus, No Wait...
Again, this list uses a single instance of an issue to represent a recurring issue as a whole. This time, the thing the producers want viewers to forget is that the same massively important historical event happens multiple times in Doctor Who, usually in seasons only a couple of years apart, and each time the same event has a different cause. The audience often has a short collective memory, yes, but these faux pas will make you wonder whether the writers even cared. The most breathtaking example of this sin is the creation of the universe itself. As all fans know, the Big Bang was caused by the spaceship exploding in the four-part story, Terminus, featuring Peter Davison as the Fifth Doctor. Except... wait... no, the universe was created by a different spaceship exploding in the radio adventure Slipback, just two years later with Colin Baker as the Sixth Doctor. This continuity error wasn't the only reason the radio show was panned. In the case of Slipback, perhaps most of the story itself should be collectively erased from memory, too. Surely the Big Bang has been the only example of this historical double dipping? Well, no. Atlantis has been destroyed multiple times in Doctor Who. We see Atlantis destroyed in the Second Doctor story The Underwater Menace before, forgivably, perhaps, its fate is presented in a different way in the later Third Doctor story. Then, just the very next year, in another Third Doctor story, The Time Monster, fans witness Atlantis being destroyed again. But that's not all. Moving into the world of prose fiction, the Torchwood novel, The Undertaker's Gift, also provides an explanation for Atlantis's destruction and, while various other audio stories and books have attempted to stitch all these versions of events together, it's still enough to make a fan's head spin. Let us never speak of Atlantis or the Big Bang again.