“I couldn’t care less.”
“I could care less.”
They’re two little phrases that convey opposite meanings, yet they’re almost always universally understood to mean the same thing: that the speaker isn’t interested — and, in fact, couldn’t be less interested — in whatever’s being discussed.
So which one is the correct one? This: “I couldn’t care less.”
It means, literally, that it’s not possible for you to care less, which is to say, you don’t care at all.
People who say, “I could care less,” are actually saying that it is possible they could care less than they do, which can only mean that they do care at least a little.
Does it really matter? It does if you’re trying to be understood as completely as you can be. And once people know the difference between the two, it becomes one of those little mistakes that you can’t help noticing.
And the person who uses the wrong one is the one who ends up looking bad.