Maybe some people are mystified as to why I complain about it so much.
So, bearing in mind that a lot of it solidified when I was 15 and that starting with Space Marines would be cheap...
The Imperium of Man
It's a shitass place to live! It has only ever become more shitass as I turned more leftist.
BUT!
It is a welcome breakaway from a lot of sci-fi universes where the Default Human Faction is Space US: "we're blue, we do diplomacy, we have science going." It's an ossified stereotype, it's Star Trek's Federation without the communism.
The Imperium of Man is decidedly none of that.
It holds the galaxy in its grip. Its nominally ruled by a dead god. It doesn't do diplomacy - it either consumes (if you're human) or destroys (if you're non-human or annoying-enough human).
Instead of bland, featureless sky-scrapers, the cities are cyclopean gothic monstrosities festooned with skulls (real and artificial) and gargoyles - or exist as hives where billions cram into spires reaching into the atmosphere. Instead of gunmetal grey ships that could fit into a dozen similar settings without anybody noticing, it has kilometers long flying cathedrals fortified for ramming. Instead of bland, smooth tunics, everyone looks like they katamari'd through a museum.
The masses aren't clean-cut mostly-white people taking automated pavements to manicured parks. They're wretched, transformed by crude bionics (sometimes to the point of becoming less man and more of a tool for a singular task), and they're dressed in heavy baroque clothing. Still mostly-white. Everyone has tattoos, weats religious trinkets, and carries gadgets you could only guess at the function of. Zealous preachers in mobile pulpits, cloned babies converted into bionic cherubs and skulls float over them.
Whereas most sci-fi human armies are just USMC in Space, the Imperial armed forces are decidedly not that. From the apex superhuman killers of the Space Marines to the lowly Guardsmen faced with foes that almost always outclass them one-to-one, they wage wars on scales unseen anywhere else with a mix of technology that's either ancient, misunderstood, or a mixture of both.
Those forces are additionaly augmented by warrior nuns, weird tech cultists, and yet stranger stuff. There's an entire sector of the internal security apparatus designed to combat literal demons.
If most settings define progress as "liberalism with increasingly faster space ships," 40K measures it in dead enemies. Imperium's weapons have been passed down via generations, developed in a prosperous age log gone, rediscovered and repurposed.
The whole human civilization is living on cannibalizing the remains the remains of past golden ages just like post-cold war societies exist on eating the socialist benefits put in place when Communism was a threat and you needed to placate people. It's like Rome: crumbling, sure, but still extremely big - and extremely dangerous.
The Imperium spits on "rationality" and "common sense", it's gleefully atavistic and anachronistic in a way that's usually reserved for the ones opposing Vanilla Sci-Fi Humanity - and yes it has been around for ten thousand years.
Nothing in the Imperium works the way that sci-fi taught you to expect a future human society would work. Fuck you.


