I am routinely dazzled by an author's ability to describe the physical world--the landscape and people. It is much easier to write about abstractions—ideas, thoughts, theories—than it is to paint a word picture, or at least I find it so. Which is why I am blown away by a paragraph like the following, from the first page of That Old Ace in the Hole:
"Gradually the ancient thrill of moving against the horizon into the great yellow distance heated him, for even fenced and cut with roads the overwhelming presence of grassland persisted, though nothing of the original prairie remained. It was all flat expanse and wide sky. Two coyotes looking for afterbirths trotted through a pasture to the east, moving through the fluid grass, the sun backlighting their fur in such a way that they appeared to have silver linings. Irrigated circles of winter wheat, dotted with stocker calves, grew on land as level as a runway. In other fields tractors lashed tails of dust. He noticed the habit of slower drivers to pull into the breakdown lane--here called the 'courtesy lane'--and wave him on."
We see the land, get a sense of the character's feeling about the land through what he observes, and learn something about the people on the land.
Proulx can also vividly show us a character:
"Sheriff Hugh Dough was forty years old, a small man, five feet five, 130 pounds, riddled with tics and bad habits, but nonetheless a true boss-hog sheriff. He had a sharp Aztec nose, fluffy black hair ands black eyes like those in a taxidermist's drawer. A line of rough pimples ran from the corner of his funnel mouth to his ear. His uniform was a leather jacket and a black string tie. He had been a bed wetter all his life and no longer cared that he couldn't stop. There was a rubber sheet on the bed and a washing machine in the adjacent bathroom. He never married because the thought of explaining the situation was unbearable. He was an obsessive nail biter. He counted everything, courthouse steps, telephone poles, buttons on felons' shirts, the specks of pepper on his morning eggs, the number of seconds it took to empty his bladder (when awake)." (page 49)
Every detail helps us see and understand something about this sheriff. We don't understand everything because we can never understand everything about another person. Heck, we don't understand everything about ourselves. But a bed-wetting sheriff who cannot marry because of it.... Wow.