All throughout the Star Wars trilogy (yes, we're calling it a trilogy, and always will) the enemy Stormtroopers spend almost every battle firing wildly, missing slow-moving targets, and are generally unable to land a shot roughly in the same zipcode as the good guys. But we know they're not incompetent: We see their handiwork elsewhere in the movies -- like when our heroes stumble across a destroyed sandcrawler -- and Obi-Wan Kenobi himself even says: "These blast-points... Only Imperial Stormtroopers are so precise." These are supposedly squads of cold, calculating, efficient murder machines, professional soldiers literally bred for the purpose.
Yet, the second you put an Alderaan Princess in front of them, you've got five Stormtroopers missing a stationary target roughly eight feet away, three firing their guns wildly into the sky, and one asshole trying to ride his blaster rifle like a pony -- and none making the shot.
Fans jokingly refer to it as "Stormtrooper aim." But it's not lazy film-making (or at least, not just that): There's actually a perfectly logical, scientific reason behind this behavior. Soldiers in real wars behave in exactly the same way.
In one war-time study, a Brigadier General found that "only 15 to 20 [percent] would take any part with their weapons." And that this was consistently true, "whether the action was spread over a day, or two days, or three." Eighty percent of the soldiers would not fire, due to nothing more than their innate desire to not take a human life. We also know that the vast majority of shots fired in battle, miss.
It's hard to aim at a man and pull the trigger. Even in firing squads, it's standard practice to give some soldiers blanks or unloaded rifles to diffuse the responsibility of killing amongst all men equally. This actually makes the soldiers more likely to pull the trigger, thinking their gun might not be loaded, as well as easing the men's consciences after the fact by letting them believe there's a chance they didn't actually kill the victim.
But we all know it was you, third from the left. You bastard.
But even supposing you buy this explanation, there's one glaring omission we've left unaccounted for: If all of these Stormtroopers are missing on purpose, why don't the good guys seem to have the slightest problem murdering a city-bus worth of dudes every time they stop for gas? Are they more accepting of the brutal realities of war? Are they more faithful in their cause? Are they just a bunch of fucking sociopaths in space vests?
Nope. It's the helmets.
That's right: If the Stormtroopers had just taken off their helmets, they would have probably won the war. Especially considering that they're an elite battalion of well-funded techno-warriors, up against a space hillbilly, a gigolo, a pampered socialite and a furry version of Sloth from the Goonies. It all comes down to the basic principle of dehumanization.
Could you pull the trigger if Darth Vader looked like this?
When you remove human qualities from a person, you make it much easier to justify acts of violence towards them. In our real life militaries, this is usually done through propaganda: Those aren't people you're shooting at, son. They're japs. They're gooks. They're Muslims. They're whatever other label the military wants to fill in, as long as it makes them different -- and therefore less -- than real people.
Now remember that very first study: With that conditioning, we've only managed to convince twenty percent of the soldiers to kill another human being. No matter how much propaganda you inundate them with, when it comes right down to it, they still have to look another member of their species in the eyes, and then kill them. But imagine how much lower that holdout number would be if every single enemy combatant was encased in head-to-toe armor that de-accentuated every human aspect of their body, each suit was completely indistinguishable from the next, and the whole effect served to make them look very much like one of the many, many lifeless robots that already occupy this fictional world.
See for yourself. Which of the following would you feel bad about shooting at?
Han, Leia, and Luke don't see a person giving his life for the empire, because he thinks it's the right thing to do, or because he was grown in a vat for it and never had a chance to choose -- they see an anonymous, faceless, evil robot. No different from the three million other identical soldiers standing next to him. And the same holds true for the Stormtroopers: In the bigger battle scenes (like Hoth), they have no problem gunning down rebel footsoldiers. Rebel footsoldiers...in uniform. All identical, all no longer "people," just enemies. Look at how deadly accurate they become when facing the uniformed soldiers in the opening scene of Episode IV:
But later our heroes come running by -- the only ones out of uniform -- and the battle-hardened Stormtroopers see a charming rogue, a pretty young girl, and a naive farmboy just trying to get the hell off the giant murder planet that's tooling around the galaxy shattering worlds. Hell, they don't want to look like a coward or nothin', so they have to take the shot -- but maybe this time (just this once) the shot goes a little wide. We all make mistakes, right? Who's gonna know?
That's right; the Stormtroopers lost because they were too human.
The theory may not be perfect, we admit, but it's a hell of a lot better than just assuming the technologically superior, elite empire gave everybody shitty guns because they thought it was funny.
Because that's the official explanation.