I've always been a fan of the illusion of choice. Make multiple plot hooks for the same quest. For instance, say you characters come across a worried woman, who explains her husband was kidnapped by goblins, which you planned on leading into a larger questline. If they ignore the quest, then have them stumble upon his corpse (make sure they don't know it's him, to avoid railroading accusations) outside of town or something, say, on a trail or outside a cave, with clues leading you on to your planned adventure.

That way, you're happy because you don't have to expend effort writing multiple concurrent quests (and freeing you up to using them or their elements/ideas in your planned quest), and they're happy because they feel satisfied they'd made the right choice all along.
It may seem dirty, tricking your players, but it's the difference between having a campaign a mile wide and an inch-deep, or a campaign an inch-wide and a mile deep.

Just know that you should never, under any circumstances, act like this DM.