In most modern writing, the character will be a viewpoint character who’s actually part in the scene. However, the principle still applies in stories told from a viewpoint outside the story (e.g. the famed third-person omniscient narrator). Even a disembodied anonymous narrator has a persona, revealed by what details are presented. You get a sense of the narrator by where (s)he “aims the camera” and what words the narrator chooses to use.
Let me point out something else important about the descriptions I’ve quoted. Effie gets two sentences; Miss Wonderly gets two paragraphs. That’s an example of what I call wordspace. Here’s my rule of thumb: The more important something is, the more words it should be given so that it registers in the reader’s mind with appropriate strength.
Pacing, Not Padding
Devoting more words to something important isn’t padding, it’s pacing: building up something so that it doesn’t go by too quickly. Readers need time to absorb and appreciate what’s going on; otherwise, they don’t have a sense of the relative importance of your story’s elements (e.g. Miss Wonderly is much more important than Effie).
Of course, there can be exceptions. Sometimes you may want to brush quickly past something important so the reader doesn’t pay much attention. This is common in mystery stories, where crucial clues may be downplayed in order to sneak under the reader’s radar. Sometimes too you may choose to hit the reader with a passage that’s short and brutal rather than drawn out: you smack the reader’s mind with a hard sharp impact.
Still, most of your writing will follow the general principle: more words, more importance; few words, more forgettable. It’s comparable to the use of slow-motion in movies—when the hero finally punches out the villain, you don’t just let the punch fly past at full speed, over and done with in a fraction of a second. You slow it down; you show the impact and the villain being knocked backward; maybe you show it several times from several different angles. You show that this punch is The One that every other punch was leading up to. To do that, you have to give it enough time to happen.