On the topic of the Time War, it's the biggest and most climactic battle in the history of the entire universe so how come nobody seems to know for sure how it all even started!? That's true of most wars in a way. The reasons behind them become blurred as the unnecessary carnage continues but the origins of the Time War have remained particularly elusive over the years. Former showrunner Russell T Davies, who introduced the concept of the Time War alongside the Ninth Doctor back in Series 1, has suggested that it was various events throughout the Classic Series that contributed to its outbreak, most notably the 1975 Fourth Doctor serial Genesis of the Daleks (in which the Time Lords sent the Doctor back in time to avert the Daleks' creation) and 1988's Resurrection of the Daleks (featuring the pepperpots' attempt to infiltrate the High Council of the Time Lords using a duplicate of the Fifth Doctor). While the defining catalyst remains unclear, perhaps it's just easier if fans accept that the Time Lords and Daleks are two formidable races that are never, ever going to get on and be done with it. There are certainly a lot of foreboding clues scattered throughout the show's history to pick at, though, if you've got some time to kill on a rainy day... It was the war to end all wars (though, evidently, it could't quite end Gallifrey...) and perhaps it's better if the truth behind its origins is never revealed. Suffice to say, it was a long time in the making.