Canonicity may be the most important thing.

dictionary.com defines "canon", as relevant to this post:

3. the body of rules, principles, or standards accepted as axiomatic and universally binding in a field of study or art.

The important qualification here is that in any field, in order to be canon, it has to be consistent with itself. If one place says James T. Kirk was born in Iowa and other place says he was born on Vulcan, that can't be canon.

That said, let me point out that the eighth Doctor doesn't exist. He never did and he never will. "Wait!" shout Whovians from around the globe. "Yes, he does! He was played by Paul McGann."

Before you Whovians get too bent out of shape, you should know that I'm one of you. The first companion I really, really liked was Zoe Heriot. You remember her, don't you? My favorite T-shirt reads, "Keep calm and don't blink". You know what that's about, of course. "Blink" vies for being the best episode ever written, right up there with "The Brain of Morbius" and "Enlightenment".  But none of that makes the eighth Doctor exist.

It's all about canonicity, and the hypothetical eighth Doctor breaks it.

You see, I'm something most Whovians aren't: a writer. With an estimated four million words under my belt (more than a million are available on Amazon), I have some experience locating and fixing plot holes, which are what you call broken canonicity on a smaller scale. Such as when I had Erik and Jaxidreshny hiking for days through the forest while she was carrying an instrument that could transport them light-years. After a while you get sensitive to those things. Don't worry, that issue with Erik and Jaxidreshny is long since fixed.

Fans are usually pretty good at finding such holes, such as, "Why didn't the Eagles just fly them to Mount Doom?" They usually can work out some kind of explanation to cover the hole, but it remains a good question. There even exists an argument that such was exactly what Gandalf told them to do in Moria when he said, "Fly, you fools!" But even dredging out those inconsistencies, fans are eager to accept everything they see without serious questions. After all, that's the way it happened in the fictional world.

Doing so is quite a bit harder for a writer, who spends thousands of hours trying to get rid of exactly those issues. You can't spend decades thinking about personalities, motives, emotions, what works and what doesn't, then blindly accept what doesn't work.

There are certain things you just don't do. You don't put Darth Vader in pink tights and a tutu unless you're doing parody. You don't have Captain Kirk totally screw up, destroying himself along with the Enterprise and ending the series prematurely. You don't have Superman raping little girls. You don't turn the interior of the TARDIS from a clean, functional design to a ghastly trash heap (which, unfortunately, they kept for the series reboot). You don't suddenly make him half human when for 26 seasons he was faithfully and totally a Time Lord. You don't bring back the Master as a creeping glob of snot. You don't have a protagonist who could virtually ignore women he traveled the universe with suddenly go all goo-goo over a woman he just met. (What heterosexual male wouldn't notice Zoe Heriot?)

To make matters worse, they started the new series with a "you don't". The Time Lords were all destroyed? Now, that's news! How do you suppose that happened? Did all those Time Lords scattered throughout history just decide to return to Gallifrey at a certain moment in time so they could all conveniently be wiped out? It makes no sense! It is logically inconsistent with the 26 prior seasons. These aren't Pacific Islanders in the 1800s; these are Time Lords. That may be the biggest Doctor Who gaffe of them all.

But Doctor Who is not what keeps me up at night grieving for the future of all that is sane. What does is the greatest canonicity busting faux pas ever to take place in the fictional world: Ron Weasley and Hermione Granger.

I rooted for Harry and Hermione as a couple from early in the first movie, and when I saw it going the wrong way in Goblet of Fire, I lapsed into denial and insisted it couldn't be so. Reading the latter books nearly drove me into depression, and it had nothing to do with the fact that "Hermione Weasley" just sounds terrible. If you keep up on Harry Potter at all, you'll know that Rowling later confessed to having made a mistake putting Ron and Hermione together:

“I wrote the Hermione/Ron relationship as a form of wish fulfillment. That’s how it was conceived, really. For reasons that have very little to do with literature and far more to do with me clinging to the plot as I first imagined it, Hermione ended up with Ron.”

“I know, I’m sorry,” she adds. “I can hear the rage and fury it might cause some fans, but if I’m absolutely honest, distance has given me perspective on that. It was a choice I made for very personal reasons, not for reasons of credibility. Am I breaking people’s hearts by saying this? I hope not.”

No, duh! But she's a writer; she'd have to have noticed eventually. Attend to her comment, "...not for reasons of credibility." She knows the Ron/Hermione hookup is not credible. It didn't surprise me she made that admission, but it surprised me it took her so long. Erik and Jaxidreshny, whom I mentioned above, aren't even the same species, come from worlds 117 million light-years apart, and have completely different societal structures and understanding of sex, yet they're a more believable match than Ron and Hermione. Even if the ill-fated wizards made it to their vows, they never would have had children because they'd be casting Avada Kedavra at each other before they ever made it to bed. I'm surprised Rupert Grint and Emma Watson could play romantic scenes between them with straight faces. I knew it was Harry and Hermione from the moment they met on the train; it's unfortunate the writer didn't until it was too late.

A lot of fans exploded in claims of heresy over this, and some of them wrote articles picking through the interview to find a way to believe she didn't really mean what she said. "Oh, Ron and Hermione will be all right with some counseling." Like hell, they will! I've done some counseling. The incompatibility between them is not a matter of learned behavior, of anything that would benefit from psychoanalysis. It's a basic clash between their personalities, and no amount of counseling is going to change that.

Ron and Luna would have worked; they're compatibly loopy. Ginny would have worked with either Neville or Dean.

So all this leaves me with a problem. If I accept the nonsensical parts as written, I can't really enjoy the story. Rule number one in fiction: don't break the suspension of disbelief. And baby, the cases I've mentioned break it big time, more than fourth wall gags. They scream with the volume of Krakatoa that this is a STORY and someone flubbed the plot. In order to enjoy it, to pretend it's real, to immerse myself in it, I have to mentally edit out the parts that don't add up and where necessary replace them with something that does. That scene on the Hogwarts Express platform at the end of Deathly Hallows had to have arisen from Hermione (Harry's wife) and Luna (Ron's wife) taking polyjuice potion as a practical joke on their husbands, which makes a lot more sense than Ron and Hermione discovering mutual tolerance. I have to omit the eighth Doctor and ignore that nonsense about the Time Lords being destroyed. Not to do so ruins everything for me because they demolish the credibility of the story line.

It's more than just "I wouldn't have written it that way". Under that category is that I would have had Draco suffer more serious consequences from his death-eating days, and I probably would have hooked him up with Pansy if I hadn't had Hermione kill him in battle. I would have had Voldemort hide his horcruxes in more secure locations, such as the bottom of the Marianas Trench. Those details don't constitute gaping plot holes, so they're not that big a deal. Putting Ron and Hermione together is. You can't carefully develop their personalities over the course of seven volumes and finish it up with, "But let's forget all that. It was a joke."

So I'm just wondering. Is anyone else compelled to fix broken plots in their mind to avoid terminal insanity?

Yikes! I wonder if anyone has done that with any of my works!