Slate is featuring this article which attempts to explain the appeal of the movie, "The Matrix." Some of this is right on the money for me, in that the movie represents a kind of ultimate "Walter Mitty" adventure for computer geeks. However, I think the author failed to emphasise what, to me at least, is important about it, and in fact is important about nearly all good science fiction.
In The Matrix the filmmakers created a completely new world. But, and this is something "mundane" screenwriters seem to have a really hard time getting their heads around, that world has rules. We may not know them, we may not completely understand them, but by watching, reading, or listening carefully we can begin to tease them out.
As we tease them out we get to play games with them, turn the movie or book literally into "science" (using observation to hypothesise rules, make predictions with those hypotheses, test them by further observation) "fiction" (in a fake world). We try to get our head around how a particular kind of faster-than-light (FTL) engine works as it is introduced. Later on, when the heros get in trouble because this FTL engine has broken down, we put ourselves in their place. What would we do if we needed to fix this thing? How would we get ourselves out of it?
In good science fiction, the authors (who presumably already know in at least a vague sort of way what makes it all tick) use rules to figure out what is going to happen. In really good science fiction they use these rules to make completely unexpected, and yet at the same time consistent and logical, plot corners and twists to get our heros out of their jam.
It doesn't even have to be "hard" science fiction. Everyone knows Dr. Frankefurter is a really weird crossdresser with a penchant for singing and a tendency to vat-grow bodybuilders in gold lame' speedos. But he does a lot of other weird things, ones that have a pattern, but which for some reason just don't quite stitch together. It is only when Riff-Raff and Magenta reveal their true nature that it all falls into place. A weird, twisted, ambiguous, and funny place, but a place nonetheless.
This consistency, the ability to build not just fancy spaceships or shiny guns but entire worlds, cultures, whole universes, is not easy. Whole chunks of Hollywood all too often think creating the former automatically leads to the latter, and then wonder why Earth 2 bombs while Babylon 5 thrives.
When the computer is just a computer, the girl is just pretty, and the hero simply quick with his hands, well, it's just another flat, cynical attempt by people who Just Don't Get It. It's only when the computer is a self-aware monster with an agenda and a history, the girl someone with a past that controls her reactions, her fears, and her hopes, and the hero simply a normal guy trying to figure it all out before it gets him killed, that it becomes something magic.