(And I for one will never understand the attitude of some fans that being consistent is more important for a work of fiction than being entertaining.)
I suppose it depends on how 'into' the universe you get. I remember being a kid and just being completely addicted to the books, and finding so many ways to nitpick them... incessantly! I wanted them to be in genuine continuity.
I'm the same way, but I wouldn't want to settle for a mediocre story just so I could fit it into continuity, and I think a brilliant story is still a brilliant story even if it doesn't fit into continuity. I like consistency, but I don't understand why anyone would define as the single overriding determinant of a story's worth or right to exist.
It's like this:
Every time I read Chapter 1 of
Harry Potter and the Half-Blood Prince, I get mildly irritated. Why? Because when the Prime Minister of the United Kingdom recalls the first time he met the Minister for Magic, Cornelius Fudge, he remembers Fudge telling him that his male predecessor had tried to throw Fudge out of the window, thinking Fudge to be a hoax from the Opposition.
Why does this bother me? It bothers me because Chapter 1 of
Harry Potter and the Half-Blood Prince takes place in 1996. In 1996, John Major was Prime Minister. His predecessor was Margaret Thatcher.
Ergo, every time I read Chapter 1 of
Harry Potter and the Half-Blood Prince, I get irritated, because that detail interferes with my suspension of disbelief. That is to say: I like, when I'm reading
Harry Potter, to pretend to myself that it's all absolutely real, that the events of the series occurred simultaneously with real history as it actually unfolded between 1991 and 1998, and that if we could only get past that darned Ministry of Magic, by jove, we'd get to visit Hogwarts, too. And when I see a detail in the
Harry Potter world that contradicts real life, that interferes with my ability to pretend that it's real.
For a lot of people, apparently, any inconsistency within the Trekverse interferes with their ability to pretend that it's real.
Now, I know full well that my reaction is not particularly rational, and that I shouldn't let it get in the way of enjoying -- or telling -- a good story. And in point of fact, that's how I try to regard things like the Arthurian legend. But I do at least understand the impulse to put everything into a giant box. I think it's bad and arbitrary and limits creativity -- but I'd be lying to say I don't sometimes have that urge, too.