Here is part of a sentence I encountered in an article on mid-life suicide: "When Liz Strand’s 53-year-old friend killed herself two years ago in California, her house was underwater and needed repairs, she had a painful ankle that was exacerbated by being overweight . . ."
But if one's house were underwater, one could just swim from room to room. How then could being overweight exacerbate ankle pain?
A house fit for normal human habitation cannot be literally underwater. But it can be 'underwater,' i.e., such that the mortgagee owes more to the mortgager than the house is worth.
The omission of necessary 'quotation' marks is the opposite of that sure-fire indicator of low social class, namely, the addition of unnecessary 'quotation' marks. See The "Blog" of "Unnecessary" Quotation Marks.
Some of my conventions:
1. When I am quoting someone I employ double quotation marks.
2. When I am mentioning an expression, I never use double quotation marks, I use single 'quotation' marks, e.g., I write:
'Boston' is disyllabic.
Suppose Ed Koch (1924-2013) had said,
Boston is a 'city.'
The marks signify a semantic stretch unto a sneer. This is not a case of mentioning the word 'city,' but of using it, but in a extended sense. Had old Koch said that, he would have been suggesting that Boston is a city in a merely analogical or even equivocal sense of the term as compared to the city, New York City.
3. So the third use of single 'quotation' marks is the semantically stretching use. The sentence I just wrote illustrates it inasmuch as this use of 'quotation' marks does not involve quotation, nor does it involve mentioning a word as opposed to using it.
This is a much trickier topic than you might think, and I can go on. You hope I won't, and in any case I don't feel like it. But I can't resist a bit of commentary on this example from the blog cited above:
This might just be an example of a misuse of 'quotation' marks. But it could be a legitimate use, an example of #3 above. They want your excrement.
If you want to emphasize a word or phrase, italicize, or bold, or underline it. Don't surround it with 'quotation' marks. Or, like Achmed the Dead Terrorist, I kill you!