Pauldrons
In the grim darkness of the far future/Renaissance Europe, there is only war. Unless you have Imperial power armor/Chaos Plate or Norscan Marauder's hide armor, in which case there is also pauldrons. Pauldrons are the sections of armor that cover the shoulders, and are well known for the tendency of artists drawing Warhammer 40k material to make them ridiculously huge. World of Warcraft armor also tends towards oversized shoulder-plates. (Fuck you Blizzard!)
In the far far future... Manliness is measured in the size of your pauldrons.
It is theorized that position in Imperial society is directly related to how large your pauldrons are, as exemplified by artwork of the Empra himself, who has power armor with pauldrons so massive he cannot see over his own shoulders or raise his arms to more than a forty-five degree angle.(Imperial Power armor bypasses this inhibition by having their pauldrons being automated. Thus when an Astartes must look over his shoulders, the pauldrons will automatically lower. As for moving their limbs fluidly, one must keep in mind that the average Space Marines has tremendous physical strength, and thus would be capable of lifting his arms fluidly despite the weight of the armor.)
Those unfortunate enough not to be equipped with power armor instead use the size of their hats in a similar manner.
Privateer Press has copied the style of the huge pauldrons of Warhammer 40k and added comically large pauldrons to some of the characters in its Warmachine game, mostly the Khadorians and "Lord No-Peripheral-Vision," Vlad Tzipesci, though the Great Bears of Gallowswood are certainly not innocent.
Summarised In a Chaosy Fashion
Our enemy wears METAL BAWKSES, DA COWARDS, DA FUHLES! we... weeee shall wear bigger metal bawkses...
Summarised In an Orky Fashion
'ERE BOSS, YOO WAN GET US SUM OF DEM SHINEY PLATES?