So when you're improving (e.g., Sandbox Style) because the player says "I want to do X."

1. Your next step is to ask "why" (so you can figure out how to make this interesting).
2. You then need to come up with some obstacles to make this interesting (otherwise nothing really happens).

Can someone list out the generic "go to" obstacles they use (it's probably something that's implicit). e.g.,

- the person won't give you X (until you do Y for them);
- someone else doesn't want you to do X;
- getting X will cause something unexpected to happen;

etc.

When designing a sandbox, trying to think of everything the players may want and then scrambling to find ways to make it interesting is a tiring game with a lot of wasted effort.

Concentrate on the sandbox environment, and the people and monsters that inhabit it. Sometimes its hard to determine what the players really want and it may change often. The npcs & monsters YOU create for the game are much easier. What do THEY want? What resources do they have? What plans do they have for getting what they want?

All of these can be detailed before the players arrive on the scene. Once the players start messing around in the setting then they will discover some or all of these things going on. Some of them the players may wish to thwart, and others they may wish to aid, while others may get ignored.

No matter how the players interact with these things, there will be consequences arising from their action or inaction. The DM should provide enough information via rumors or other devices for the characters to check out, but the players have to take an active interest in adventuring.

If you have set up a dynamic environment that exists on its own then these questions are already answered.

The 5e DMG has various random tables for things like this.

RNG based freeform can be a very different animal than on the fly freeform or pre-planned freeform. You can even mix and match.

Everyone has different approaches.

Quote from: PencilBoy99;847437So when you're improving (e.g., Sandbox Style) because the player says "I want to do X."

1. Your next step is to ask "why" (so you can figure out how to make this interesting).
2. You then need to come up with some obstacles to make this interesting (otherwise nothing really happens).

Can someone list out the generic "go to" obstacles they use (it's probably something that's implicit). e.g.,

- the person won't give you X (until you do Y for them);
- someone else doesn't want you to do X;
- getting X will cause something unexpected to happen;

etc.

Remember an old principle of theater.

"Everybody in a scene wants something.  Each character will do whatever they can to move events so that they get what they want."

The butler may simply want to deliver the drink to His Lordship and get back below stairs to finish his cigar.

The mob boss may want His Lordship to buy into an illegal scheme.

Et cetera.

So figure out who the PCs have to interact with, and what they want.

Major NPCs, you should already have some idea what they want.  And don't be afraid to tag NPCs with one-line descriptions of characters from movies.  You don't have to let players know that the Mob Boss is Fezzini from "Princess Bride" and thinks he's much smarter than he really is, and tries to show off his intellect.