Doozers Do

Don't ask me why, exactly, but I was looking up Fraggle Rock on Wikipedia and came across the reason Doozers (the little green guys in the hard hats) are constantly building. Turns out the they need to do it to survive, and therefore the Fraggles eating their construction is not a menace but a lifesaver (which also accounts for the line in the first episode of the series - which I just happened to watch - where one Doozer says to another "architecture is meant to be enjoyed"). I especially liked this story:

This symbiosis becomes integral to an episode where Mokey calls upon the Fraggles to stop eating the Doozers' constructions - because they spend so much time making them. Fraggle Rock quickly fills with constructions and the Doozers have no space left in which to build. After running out of space, the Doozers finally decide to move on to a new area because the Fraggles won't eat their constructions, and there is even a tragic scene with a mother explaining to her daughter that Doozers must build or they will die, and so they must find a new place to live where they can build and hopefully find Fraggles who will eat their constructions. Overhearing this, Mokey realizes that she has inadvertently disrupted a vital symbiotic relationship through ignorant good intentions. As a result, Mokey frantically rescinds her prohibition and encourages the Fraggles to gorge on the structures -- just in time to persuade the Doozers to stay.

Jim Henson had some very interesting ideas.