In Dungeon and Dragons & other roleplaying games, the system or campaign is not as important as the players. As a dungeon master everything you do should be based around these players.
From creating, and preparing magic items to which monsters to run and scenes to plan.
This idea is very well represented by Review the characters from Return of the Lazy Dungeon Master
This does not mean every player is equally or even invested in your game.
Is something important for the enjoyment of players.