[RiderOfGiraffes]

  > I could care less, ...

I don't want to be "that guy" and I'm not trying to be a grammar Nazi. I know this is now an idiom in the USA, and therefore it doesn't have to make sense.

However ...

I've now heard it said, in four different countries, that this phrase makes the speaker sound like an idiot. I know it's now just "the norm" in the USA, but I wanted to let people here know that saying this makes a bad impression.

If you don't care how you sound to non USAians then don't bother. But if you're wondering what I'm talking about, David Mitchell does an excellent job of explaining "I couldn't care less"

http://www.youtube.com/watch?v=om7O0MFkmpw#t=0m56s

I now return you to your normal programming.

[tsuipen]

Let me play devil's advocate (which might actually play in your favor, seeing as you've used that neologism). How do you think new words and phrases make it into the dictionary? It's by a proportionate amount of people using it for a specific meaning. Meaning is an abstract concept. Contrary to popular belief, language is not always logical or literal. It's an ever-changing organism: elastic and metamorphic.

The phrase you quote is not "now just" the norm. It has always been ever since I can remember living in North America. It's nobody's fault the British-speaking world has just discovered it. This reminds me a little of when the Europeans first discovered "America."

This is why Jorge Luis Borges once said, "Todas las palabras fueron alguna vez un neologismo" (All words were once a neologism).

[RiderOfGiraffes]

<shrug>

It's common in the USA. People I've spoken to from other countries think it makes those who use it seem ignorant. I'm providing data, not making a judgement. I know that many idioms don't make sense when dissected.

The parts of the world I have regular dealings with - excluding the USA - all say "I couldn't care less," and that actually does make sense. The people I've spoken with about this have expressed bewilderment that the alternate version should be used. They say that it doesn't make sense, and it's open to misunderstanding.

When I speak with customers I don't use the same short-hand or code phrases that I use with my colleagues. Likewise students when applying for jobs or other positions use more formal language, because to do otherwise makes them look uneducated and ignorant. I'm just saying that I've seen the same attitude towards people who use this particular phrase.

Personally, I don't care. In fact, it would be hard for me to care less. I'm just offering a datum that some might find useful.

[AaronI]

It's sarcastic in intent. Trying to condemn an idiom that is obviously logical nonsense misses the point. When I say "I could care less", it could be interpreted instead, "as if there were anything else I care less about."

[mturmon]

I could care less about what a dude with such bad teeth says.