As a species, we are tool makers first and foremost. That's why we love to see gadgets in our movies, and to watch our Captain Picards and Batmans and David Hasselhoffs defeat the bad guys with technology we know we'll never own.
But in the course of trying to dazzle us with their fancy spaceships and battle vehicles, sometimes Hollywood forgets to make sense.
#6. The Imperial Walker
The dreaded Imperial Walker, or All Terrain Armored Transport, is frequently considered the single coolest vehicle in the entire Star Wars universe.
The moment the rebels spotted these things on the horizon in The Empire Strikes Back, the only question was exactly how much of their stuff they could pack before they flew screaming off the planet.
"Fuck it! Leave the porn, leave everything! RUN!"
In addition to being huge battle robots of death, the Imperial Walkers also boast a blind spot in excess of 300 degrees. The thing can't turn its head. Specifically, it can only turn its head this much:
This is not a minor issue. That up there is an AT-AT trying to shoot an enemy ship that's flying past it. That's as far as it gets; it's like a huge, muscular guy who happens to have his head frozen in a neck brace due to a crippling spinal injury. The only difference being that guy could still conceivably punch an enemy by swinging at him wildly. Meanwhile, all of the AT-ATs guns are glued to that non-swiveling head.
"Two targets for the price of one. Nice design, Kuat Drive Yards."
This would not be a problem if, say, the walkers were extremely fast and maneuverable. For instance, in the real world, jet fighters have all of their weapons pointing forward, too. But they also go faster than the speed of sound. These bastards, on the other hand, have the top-speed of a Geo Metro driving across a river. It takes them what looks like an entire day to execute a full U-turn. That's good news for you if you're Luke Skywalker, because if you get within 20 yards of one, it can't hit you to save its life.
Years of additional weapons development actually lead to shittier war machines.
Also, the Empire seems to have constructed the Walkers without considering that most militia battles are not fought thirty stories above ground, so the tank commanders spend the entire day on Hoth with their chins to their chests trying to see what the hell they're supposed to be shooting at.
The only reason the rebels had such trouble with them is because the speeders insisted on using what Luke referred to as "Attack Pattern Delta", which appears to mean, "fly directly at the enemy in the one single spot where they are able to shoot us."
#5. The DeLorean Time Machine
While Doc Brown may not have been entirely up front about the potential dangers of time travel, it is possible that he simply ironed out the DeLorean's disastrous defects off-screen when be built that steampunk time-train.
Sure, Dr. Brown probably could have invested all that time and effort into solving the world's energy crisis but, fuck, sometimes you gotta make yourself happy.
One of the major plot points of Back to the Future, Part III is how they can't start the DeLorean without some gasoline.
This is not just a case of bad luck. This is pretty much a fatal flaw for any time machine.
The DeLorean DMC-12 was built by douchebags for douchebags, with sleek lines to murder air friction and gull wing doors that flared open like a peacock's tail to attract more douchebags.
We don't know who owns this gold-plated DeLorean,
but we'd be willing to bet they wouldn't look out of place on the cast of Jersey Shore.
It's the kind of car that can only exist in a society with paved roads and a steady supply of the specific kind of refined fuel the engine is capable of burning. Both are things that 99% of the places you would go in a time machine will not have.
A utility vehicle with a diesel engine would have probably been a better choice to attach the Flux Capacitor to, or at the very least a DeLorean with a converted diesel engine. They can take a beating and are capable of running on a huge range of volatile, comparatively crude chemicals from vegetable oil to bathtub gin. Doc, Marty and even Biff could have traveled to just about any point in recorded human history and found (or made) something to run their car on.
Above: the one constant in human history.
Though, all of this just begs the question of why the DeLorean had an internal combustion engine at all. Before Doc Brown went back to the future he spent his first trip tricking out the DeLorean with a hover refit and a Mr. Fusion generator. Great. So why didn't he rig the car up so that the generator turned the wheels, too?
Mr. Fusion could supposedly convert any organic matter into enough raw energy to molest the fabric of time and space. If it can spit out 1.21 gigawatts, it can sure as hell generate enough juice to replace the gas engine. Plus, he'd have had unlimited fuel no matter where he went.
"Look, Marty! I crammed a goddamned dinosaur dick in there!"
#4. Space Ships With Oddly Unstable Reactors
Powering up starships and space stations requires a lot of juice, we get that. We peons in the real world still depend on burning dead plants and mutated fish to generate steam, while fictional geniuses are literally conquering the universe on fusion, antimatter, and alien poop. It can't be easy to keep things from going wrong.
All of these supposedly advanced systems have an inexplicable tendency to explode at the drop of a hat.
"God dammit, who put tin foil in the microwave?"
For instance, when the main reactor fails in Star Trek they call it a "warp core breech" and it happens so often there's an entire page listing times it has happened on the Star Trek wiki. Seriously, it was like every third episode.
Their only safety measure against this was, hilariously, to "eject" the warp core out into space to allow it to explode (taking anyone nearby with it) and leave the ship utterly disabled. You know, like how when you have engine trouble on your car, your only option is to punch a button that makes your engine go flying out of the hood.
Do we even need to talk about the Death Star? Or what happens when their main reactor takes any kind of damage?
In the future, everything is 400% more explosive.
Or, for that matter, the alien ships in Independence Day? We're talking about a structure the size of a city--or larger--and the whole thing goes up like the fourth of July if you kick it in one single spot.
Why should the reactor always be the weak point of a starship, in any case? If you were designing something like the USS Enterprise, wouldn't it make more sense to make the reactor as stable as possible? After all, are the power generators of the future truly more unstable than what we work with today? Look at this thing:
That's concrete. Thick concrete. You know what would happen if you crashed a fully-fueled 767 into that? Absolutely nothing. Worst case scenario, they have to turn it off while they wash the dark smudge the plane left on the side of one of the cooling towers. See, because we know the process can be volatile, we design the shit out of it to make sure it doesn't explode.
In case you can't watch the video, it features an F4 Phantom ramming a concrete barrier. We'll give you a hint, the jet doesn't win.
You can say that it's not fair to compare a reactor on board a space vessel with one sitting on the ground, but it's actually the opposite--you'd want to engineer in even more precautions because you have millions of people effectively living in the same building as the reactor.
Imagine if they announced that they were going to build a power plant right in the center of Tokyo and that, oh by the way, if just one hillbilly crashes his airplane into it, it will result in a mini-supernova with about three seconds' warning. It would be time to send that shit back to the drawing board.