"It's your sister's wedding! Will it kill you to put on a tie?!!"
You don't have to have kids, or a sister, to understand at once the little domestic drama from which those lines are lifted.
They are uttered, almost surely, by a mother to her son – probably a teenager but possibly a style-challenged man in his 20s, or even older.
The role of sartorial enforcer is something that a copy editor can identify with, too. After all, an editor often has to say, "Look, that word just isn't right for that context."
It's a role I've been willing to shoulder over the years. I'm as much a believer as anyone in having fun with language. But I also think there's value in preserving a sort of blue blazer/gray slacks level of formality in serious writing. Maybe the most important bit of counsel I have to impart here is that wordsmiths should pay attention not only to the meaning of new words they learn, but to their tone, too – high or low? Dressy or casual?
I was first introduced to the idea of different levels of formality in language for different occasions in seventh-grade English. As an example, the question of whether it was dinner time was rendered three ways: in informal English, in standard English, and in truly elevated prose.
The informal version I remember as something like "Let's eat." The highest level of formality – intended, I think now, as something of a joke – was "Shall we indulge in a repast?" This was so completely over the top that it has remained etched in my consciousness, lo, these many years later.
Oddly, I can't recall for sure what the standard version was. It may be that it was "Shall we dine?" and I'm repressing the memory because it will make me sound as if I was in seventh grade during the early years of Queen Victoria's reign. Not so, Dear Reader, I assure you!
"Shall" as the first-person declarative counterpart to "will" has largely disappeared – from American English, at least. "I shall go with you" sounds straight out of the Brontë sisters.
But as an interrogative, "Shall we?" lives on in the mouths of grown-ups making social plans: "Shall we get a bite near your place, or do you know of a good restaurant near the theater?"
Many younger people probably hear "Shall we?" as "Should we?" In their own speech they substitute "Juwanna?" ("Do you want to?")
Shilly-shallying aside, I suspect that some writers, especially nonprofessional ones, see "informal" in the dictionary and think, "Oh, goody, that's the word I want to use. I don't want to sound stuffy."
Part of the trick in working with such writers is to argue for "standard" English, not "formal" English, which is likely to scare them.
An example of what we might call blue-jeans language where blue-blazer speech is called for comes in "My Fair Lady," when Professor Higgins takes Eliza Doolittle out to tea with some of his upper-class friends. He's worked miracles with her pronunciation but failed to focus enough on her word choice or, for that matter, the story lines inside her head. Fortunately he is able to pass off Eliza's remarkable utterances ("She done him in") as "the new small talk."
In a news article about this tea party, there would have been nothing wrong with quoting as many wonderful Eliza-isms as the reporter could round up. Having multiple levels of language within an article – the standard English of the third-person narrator; the compact language of headlines and subheads, the informal, colloquial, or even slang of the direct quotes from sources the writer spoke with – gives the piece depth. It's like a well-composed photograph with a foreground, a center, and a distant background, and maybe a person or two as an indicator of scale.
But there are still places where a jacket is required, and a writer starting out should know where they are.