"It's all about the story, man!!!"
Just kidding. We all know that it's really all about their super duper characters, and their cool super powers!!! They don't want to be challenged, they just want to romp and stomp their way through your campaign sessions.
The PCs are not the "Characters" I'm talking about here.
Yep, the campaign needs lots and lots of NPCs with their own motivations, timelines, etc. It's what makes the world feel real.
You choose not to go to investigate the mystery in the forest of Eridon, well turns out it was kinda importnt, now a portal to another plabe has been open and the world is being overrun by entities from that plane.
The owner of the tavern is being really helpful, but why? You hardly know him, what are his motivations? Turns out he's helping the slavers and he's "helping" you in order to distract you and make you go away from the town cuz he'sw expecting a ship filled with slaves.