bad story
It's not like it ever changes, either.
People: "Oh forget, Dr. Eggman found the Chaos Emeralds we hid in the last game. Now he's built something that's going to destroy the world!!"
Later...
People: "Argh, it's other people who are trying to steal the emeralds back so they can destroy the world themselves! Somehow it makes a difference who destroys it!!"
Yet later...
People: "Yay, we saved the emeralds! Let's go hide them again in a place they'll be found by the next game!"
Eggman: "And I'll walk away, sulking, and find them again! Hahahaaaa!"