Peter Jackson: I just can't fit all this stuff into one movie. Let's drop
one of the towers.
LotR Fan: But it's called The Two Towers.
PJ: Well, Barad-Dur can be the second tower.
Fan: But Tolkien explicitly stated that the two towers were Orthanc and Minas
Morgul.
PJ: It's decided, then. We'll drop Minas Morgul.
Fan: But-
PJ: Okay, let's add in some unnecessary crap that's not in the book.
Fan: But I thought you were having trouble fitting everything in already.
PJ: Yeah, because I want to add this extra stuff. How about an army of elves
that comes to help out at Helm's Deep?
Fan: But Tolkien explicitly stated that the Last Alliance of Men and Elves was
when Sauron was thrown down at the end of the Second Age.
PJ: It's decided, then. We'll add an army of elves. And we'll also have Faramir
kidnap Frodo and start taking him back to Minas Tirith.
Fan: But Faramir did exactly the opposite in the book!
PJ: Look, whose story is this? Yours or mine?
Fan: Well, actually, it's Tolkien's.
PJ: It's decided, then. We'll completely alter Faramir's character.
...ad infinitum