In written stories, we imagine the world that surrounds the characters. The odds-and-ends that clutter this imagined space come out of the clutter of our lives. Unless something is specifically described, it comes from the reader and not the author.
In visual media—with few exceptions—even meaningless knick-knacks and piles of junk have to be presented in solid form merely to create the illusion of a real world. By necessity, this must come from the creators. There is no room for imagining a scene which is pre-visualized.
Where there is room for the imagination of the audience is in the meaning of things pre-visualized. This process, however, must be kick-started. Just because a scene is dressed with piles of junk doesn't mean it will be imagined to be anything more. A clue must be given as to what else it might mean—its depth must be alluded to.
But let's back up for a second. Set dressing is an art in-and-of itself. Cobbling together an arrangement which emulates a "lived in" space requires a sophisticated knowledge of the artifacts belonging to that space and time. It also requires an understanding of the character(s) who lived in that space. A good set dresser understands that his art is an extension of the story. A great set dresser, however, understands that his art tells the story.
There must be a cohesion between the elements of a set, but this does not mean there must be similarities. In any visual media which places limited value on such background elements, it is standard practice to dress to stereotype and to use elements that are strictly contemporary to the period (especially if the "period" is now). However, you have objects in your house and in your closet that are neither indicative of your current philosophy or the current culture. This is depth.
It is important to creating solid stories that all parties concerned with creation grasp the importance of mastering depth.
The necessary depth varies by how many elements it must support to adequately tell the story. The greater the number of story elements being juggled, the deeper the root system that is needed to support it. A good rule of thumb is that the creators understand every element to at least one step beyond anything they would ever need to (or want to) tell.
Why does Hugo Reyes go by the nickname "Hurley"? I don't know, but Damon Lindelof probably does.
Fear and Loathing in Las Vegas - One the clearest examples of piles of junk telling a story that I could think of: The drug-obsessed duo of journalist, Raoul Duke and his lawyer, Dr. Gonzo, go to Vegas to cover a race. However, the real story is told through the destruction of everything the two touch. In an infamous scene, Duke awakens in a flooded hotel suite with a rubber dinosaur tail tied to his rear and a microphone taped to his face—having no idea what happened.
The Return of the King - Depth knows no limits. This visual retelling of Tolkien's classic tale certainly goes one step beyond in every area. Reportedly, WETA Workshops designed armor with runes inscribed on the inside, while John Noble, who played Denethor, Steward of Gondor, wore a heavy chain mail beneath his fur cloak. Each race of Middle Earth is decorated with its own themes, and the remains of ancient statues adorn the countryside.