I'll give you an idea of what I am talking about, and ironically it was written by M. John Harrison, the very author whose negative comments on worldbuilding inspired this thread.
Under the brow of Hollin Low Moor he slowed to a walk. His feet and ankles hurt. He sat on a rock by the path to message them, and his attention was captured by the City, waiting there in its mantle of stillness and distance. Light flared through the haze: heliographing from the riverine curves of the Proton Circuit; phosphorescing from the pleasure canal at Lowth where under a setting sun banks of anemones glowed like triumphal stained glass; signaling from the tiered vivid heights of Minnet-Saba, from the inconceivable pastel towers and plazas of the Ateline Quarter. All was immaculate -- illuminated, transfigured, miniature. It attracted him not as a refuge (although he saw himself as a refugee), nor by its double familiarity, but by its long strangeness and obstinacy in the face of Time, celebrated here in the generation (or so it seemed) rather than the reflection of light. Viriconium, the Pastel City: a little cryptic, a little proud, a little mad. Its histories, as forgotten as his own, made of the air a sort of amber, an entrapment; the geometry of its avenues was a wry message from one survivor to another; and its Present, like his own, was but an implication of its past -- a dream, a prediction, a brief possibility to be endured.
To me, this is poetry, and I don't care how much of the information is essential to the plot. It creates an atmosphere, it gives me entry into a world I could never otherwise visit.
