Overcoming setting complexity paralysis as a GM


The problem

What are the best practices to overcome that certain “complexity paralysis” that may strike a GM when trying to learn and immerse himself in a setting that has a lot of intricate background information?

An example

For example, let’s say you’re a GM who decides to give a try to running Shadowrun for the first time in your life (no matter how experienced you are in other games and/or settings.) You settle on an edition — only to realize that the game has been around for decades, and it has so much background info it could fill half the Encyclopædia Britannica (well, not literally, obviously, but you get the point).

Hesitatingly, you decide to get some focus, cut away a huge chunk of the looming material, and set your story in Redmond, Seattle. Sure, you get an official handbook for Seattle, and read through it (quickly, because gaming night is upon you) — but in doing so, you discover that there are tons of relevant, related sourcebooks (like… on magic, critters, the matrix, cyberware, etc.).

Sure, you can ignore the sourcebooks and go for a minimal approach… but even so, when you start designing your adventure (already feeling out of touch with the world of Shadowrun simply because of knowing how much you don’t know), you realize that besides the setting info, there are tons of in-game factors to consider, think through, and work into even the simplest campaign. Corporate politics and workings, magical aspects and relationships, shadow politics, gang politics and workings, the nuances of running the shadows, and so on. Of course, without reading as much as possible of the official sourcebooks, you’ll have no idea about the existence of a ton of factors — as if the sketchy stuff you learned from the core rulebook and the city sourcebook weren’t complicated enough.

And, by this time, you’re gripped by the title’s setting complexity paralysis. You’d love to run the game, but you feel you have no real idea how stuff should work, and no time (let alone a reliable entry point) into the hypercomplicated, cross-referenced lore. And with that, you return to running something you know, be it a world you’ve been following since its inception or one that you’ve built yourself. You skip running Shadowrun.

Mind you, I’m definitely not looking for answers focused on Shadowrun. It’s just an example. (Sure, it’s okay if you use it as an example for general suggestions.) I could practically have brought up quite a number of other worlds. Star Wars EU. WoD & nWoD. The Forgotten Realms. Warhammer FRP. And so on, and so on.

Summary

What I’m looking for is methods that help you, the GM, through this “setting complexity paralysis”, this disheartening and disappointing block that hits you when you face a huge amount of background material without which your game won’t feel authentic, just a bad copy, an alternate universe of an alternate universe.