d6 degrees of success with anything

Is the badger's burrow wide enough to squeeze down? Is the giant scorpion's flesh edible? Are the bars set in a stone weak enough to chip away? Will the dead tree's branch stand up to the dwarf's weight? Does the abandoned generator have any gas left in it?

You're a GM and need to determine some aspect of your world. Roll a d6. 1 is the worst plausible outcome for the characters, 6 is the best, and everything else is shades in between.

Why do this?

• It's quicker than any other rules-based approach
  
• It's helpful if you have trouble just snap deciding the answers to questions
• It's useful when something would affect the PCs, so you would be either 'handing them a win' or 'screwing them over' by fiat
• The dice can surprise you and challenge you
• When not everything has the most likely default answer, it can make a world feel more real
• There might be a rule for this situation (or one that can be adapted), but you don't remember where it is

The "crawling down the badger burrow" example:
1 - Looks barely wide enough to get down, but narrows partway through, so characters can get stuck upside down in the middle of a twisty dirt tube
2 - Isn't wide enough to squeeze through
3 - Is wide enough to squeeze down but requires a little digging around the bends
4,5 - Is wide enough for the smaller characters, but not the largest
6 - Is just large enough for everyone to get through

The "eating the giant scorpion meat" example:
1 - Is poisonous; incautious consumers suffer a minor ongoing poison effect
2 - Is mildly toxic; characters start throwing it up shortly after getting it down
3 - Is edible but tastes really bad
4,5 - Is fine to eat
6 - Is not merely edible, but delicious and keeps well

Etcetera.

The key understanding is that you don't even have to assign numbers and degrees of success before rolling. Just mentally frame - or speak out loud - your question. Then you roll, say, a 2. All you have to do is think, what's the second-worst answer to the question?

Advanced versions:

• Rarely, you'll have a question where the range of plausible outcomes are neutral with regard to the player characters. Just orient yourself on whatever axis you can find, and roll.
• Sometimes there will clearly be more possible axes than 'good' or 'bad'. Something could pose a high or low threat but offer a high or low reward, for example. Just use several dice, associating one colour with one axis.
• With a basic intuitive understanding of dice probabilities, you can determine the answers to questions about populations, off the cuff. Say you've randomly generated a group of 21 soldiers on the road. How many are in poor morale? Could really be any number of them: 1d20. How many are currently battle-ready? Probably most but not all of them: 1d8+10. How many are carrying bows? Let's guess it's likely to be about half: 2d10.