this is funny but I’m going to be a Joke Ruiner here in hopes that this might be useful to anybody looking to run a D&d game sometime for the first time.
A natural 20 always ‘succeeds’ but does not always do what the player intended to do. If a player attempts to do something Impossible, then a Natural 20 cannot make it possible, instead, have the Outcome of their Attempt be helpful in an obvious way, without being necessarily a magical Super thing.
Greg the ranger attempts to climb an 80 foot smooth marble wall with no handholds? Greg is level two? Greg does not climb that wall with a Natural 20, however, while looking for good handholds Greg spies an important clue reflected in the mirror-like surface of the wall, perhaps finding a secret catch to open a hidden door in the wall granting the party entrance to the dungeon?
Even though Greg didn’t search for the door, his incredible Luck granted him the opportunity to succeed anyways. Because that’s what a Natural 20 is. It’s Luck. A lucky swing catches an opponent off guard, even if they’re a seasoned fighter. No amount of luck will allow Susan the 1st level barbarian to shoot the God of War in the eye, but if she is Lucky enough, then he’ll be amused and impressed by her brash valor, and grant her a boon or a gift, rather than be insulted by her attack.
Keep in mind that a Natural 20 should align with what is best for the player, not necessarily what the player wants. If a player rolls a 20 while attempting to do something you know will end badly for them? Take advantage of your knowledge and have their roll instead indicate that not only does their attempt fail, it does so in a way that alerts the player to the danger of their attempt.
For example, they try to shoot a guard under the assumption he’s alone and it will be a sneaky quiet attack? Have the shot miss in such a way that the guard tells his friends just around the corner to “knock off all that racket, some of us still have jobs to do tonight!”
This kind of thing helps create a believable, consistent world for your players. Something that has rules and laws of physics of it’s own, even if those physics are a bit more fast and loose with thermodynamics than ours are. If a Natural 20 Always Works, then the world quickly loses credibility, because in that world, not only can literally Anything Happen, it has a 5% chance to do so All the Time
A world like that doesn’t really make much sense, and wouldn’t look at all like our world, and is therefore really hard for players to get attached to.
