"He unfastens his sock suspenders (let us be trivial, let us be intimate). Then with a characteristic gesture (it is difficult to avoid these ready-made phrases, and they are, in his case, somehow appropriate)...." ~V.W.--the character Bernard, describing the Headmaster in The Waves
This passage struck me as something to discuss for a couple reasons:
1. It's pretty meta, meaning that it's self-referential. Woolf talks about telling details even as she gives us telling details. His 'characteristic gesture' is told with a cliched phrase--but, as Woolf points out, it's appropriate for this character because he's cliche. (I just thought that was cool and wanted to point it out.)
2. It reveals something about details in a story: details should be appropriate, details should be character-specific, and details can appear trivial.
Appropriateness, as I'm using it here, refers to the genre of the piece. The quoted passage above is incredibly appropriate in Woolf's book because The Waves is a story told entirely through reflective soliliquies. It's whole style calls attention to itself, so a meta-like presentation of details is appropriate. This might not work so swell in a sci-fi novel or a cozy mystery. But in an experimental, literary piece it comes off masterful.
The character specificity of details is a little trickier to wrap your head around at first. In the quoted example, as I've already pointed out, you can use cliche phrases to describe a cliche character. Another example: A friend of mine is very into Eastern religions and he'd written a metaphor describing a character in Shiva-esque terms. Which is fine. Except that the Eastern motif didn't carry through the story. The character was some kind of recluse, if I remember correctly. So the descriptive metaphor didn't work at all within the context of the character...or, in this case, the context of the whole story.
Now, why are trivial details important (and, thus, not trivial)? Why on earth should we care about how this headmaster takes off his sock suspenders? Woolf points out the answer to that as well: it's intimate. Intimate moments tell more than anything else.
Intimate details are about revealing the character at their most vulnerable. The headmaster's socks are off (a 'trivial' detail, yes?)--he's surrounded by a bunch of adolescent boys--if the door opened, he'd be completely exposed, undignified. Bernard, the character telling the reader about the headmaster, chooses not to expose the headmaster, "But stories that follow people into their private rooms are difficult. I cannot go on with this story." But only after Woolf, the author, already exposed him. We now have the picture in our heads. All because of something that appeared trivial: socks.