William Faulkner once said, “in writing you must kill all your darlings.” He was a writer and nobel prize laureate so he had some idea about how to write. As it turns out that it’s also true when it comes to writing your campaign.
The phrase has evolved since then but the key meaning remains the same. No matter how much you love a character, a scene, a setting or element you should be willing to destroy them.
Forcing your favourite element into a story when it hinders your story is a mistake.
Here’s an example; you’ve got an eloquent villain, a mastermind who could shame Moriarty. He has the perfect voice for exposition, he was born to monologue! He’s a good link in your story, helping guide your players along.

Then, one dark night you wake from a dream, with a line of dialogue so perfect it ties your entire game together. Was it delivered by a celestial being? Or fiend?! You don’t care, it’s perfect. It defines the character, sums up your story in a perfect nutshell, it is the best thing you’ve ever come up with.

Now, as you’ve continued writing, you’ve suddenly seen a problem. There’s no room for your eloquent character, he needs to be replaced. You now need a brute, a tank, a monster who communicates through violence and torture.
If you try to force your killer line through the new villains mouth, it’s going to seem false, out of place and jarring. You need to kill your darling, lose the line or ruin the game.
Okay, let’s try another scenario:You just re-watched your favourite movie, about a 1300 year old goblin king trying to seduce a teenage girl, which is creepy, but the songs are cool and there’s a maze.

So you spend a week or two coming up with an amazing maze full of monsters, traps and treasure. You’ve drawn out a map, you’ve come up with mechanics for it to change, it’s got moving parts and magical locations.
It’s amazing!
You’ve set it in a mountain range a short travel in land from the port the players are currently in and you’ve got your hook. The child of the mayor has been kidnapped and must be rescued.
The next session rolls around, you’re ready, this is going to be great. The mayor rushes around the town begging for help and they …ignore him.
They were only travelling through the town and they’ve got no history here.
You see, between sessions the players decided they wanted to try the pirating life. They didn’t know how much work you’d done and you never asked because you wanted to be a surprise.

You could try and force it, suddenly it’s an underwater complex, the goblin king is now a merman! You can make it work, you think, maybe….
If you get into this situation, kill it, do the pirating story line. Do not force your maze on the players.
Save it for later, or break it apart and use elements of it for future scenarios but don’t force it. Maybe in a month or two your players will be up for the maze, maybe not.
The sooner you’re willing to kill your darlings the better. You cannot be precious about your creations and letting them go will improve your Dungeon Mastering in the long run.