Rory likes to say that we all have stories we tell ourselves. Martial arts are a part of that story. In some ways, martial arts are their own stories. They are stories about how fights happen. Almost fables, really. "This is the story of the right hook and the block that didn't work." Aesop would be proud.
Some stories are simple. Some are intricate. But every story is composed of parts. Characters, plots, settings. All the stuff you learn about in English class.
Take out a piece, and the story doesn't make sense any more. I once heard Michael Stackpole say that his greatest nightmare was to be trapped in an airport where the bookstore was filled with nothing but books that were part two of a trilogy.
Sometimes when people say that a story doesn't make sense, it's because they didn't read the whole story. Or they didn't understand something about it. I've heard a lot of people try to poke holes in the Lord of the Rings. Usually, the holes aren't holes; the person just missed part of the story.
Sometimes, though, the story just doesn't make sense. You can read the whole thing, beginning to end, and understand every part of it...but it just doesn't work. The character's actions aren't sensible. The plot takes a left-hand turn for no apparent reason. Tim Burton's Planet of the Apes comes to mind for some reason.
When you see a small part of a martial art, whether it's a technique, movement, or drill, it's like reading only part of a story. It may or may not make sense, but it helps to read the story first.
(Wim and Maija have been having an interesting discussion on Maija's post "Cheat", which provoked this line of thought. Go read it.)