Use “Much less” much less.
I try. I really do. I want to be a descriptive, rather than a prescriptive, amateur linguist. I set my laptop’s language to “Canadian English” so I could see the disparaging red lines indicating a “misspelling”, and feel smugly superior in ignoring them. But, there are still a couple of phrases that really bug me in their increasingly popular uses.
The first one, as the title mentions, is actually a set of related and roughly interchangeable phrases: “much less”, “not to mention”, “to say nothing of”, etc. They’re used in the construct “A, much less B!”- or more accurately, “It isn’t even A, much less B!” And for that to work, B has to be more intense in some relevant characteristic than A. In a bit of a paradox, B has to be much more than A. “That could couldn’t catch a dead rat, much less a live one!”-makes sense. The cat is less able to catch a faster-moving (and therefore less-catchable) rodent, because it is more elusive.
Consider, on the other hand, “I’m too tired to make dinner, not to mention calling for takeout!” It just doesn’t work. Why wouldn’t you mention calling for takeout? Being too tired to cook a full meal still leaves it on the (proverbial) table. You’d need to explicitly mention it as also being beyond your current capabilities. But if “I’m too tired to call for takeout, to say nothing of making dinner!”, then, yeah- your audience can reasonably be expected to understand that “too tired to place a phone call” includes being too tired to cook a meal, without further explication.
The other phrase that’s been causing me an unnecessary amount of self-induced strife is (and I’m going to drum up some suspense here) not (ha! see?) “I could care less.” I am more convinced by the Munroe interpretation than the Mitchell argument. I’m over the “could”/”couldn’t” debate, and I… don’t care very much one way or the other.
No, the phrase that’s been bugging me lately is “They have too much time on their hands.” (And its equally-grating sibling, “Someone needs a hobby!”) Because, look. We only have so much time here on this planet, and that phrase is usually said in response to someone who has dared to spend it doing something they enjoy, something which only offends because it’s not “productive”. I get that you don’t have any interest in thinking about writing instruments, or sci fi minutiae, or chore locales, but that doesn’t mean you’re being somehow hurt by the people who do. Really, Donald Trump is about the only person in the world who can reasonably be accused of having too much time on his tiny, baby-like hands.
I do not mean to suggest that you should stop using (or misusing) these phrases. Just as “literally” is often used as an intensifier, and “irregardless” will never be scrubbed from the lexicon, these things are very likely here to stay. But I’d rather offer my thoughts, so you can see how your word choice affects others, and at least get the satisfaction of irritating me deliberately.