When it comes to designing games, developers are always making compromises. For a universe like Fallout to be immersive as it is, every location, every NPC and every dungeon has to be laid out just so. Rules have to govern this world so it seems like a place that could actually exist. But there comes a time when being "realistic" just isn't fun (we're looking at you, carry weight restrictions). Say you blow a guy to smithereens -- by all means, his loot should be atomized along with his body. But as we know in Fallout, that's not exactly the case.