OK, I'll bite. :-D

If you say you "couldn't care less" then you don't care at all, and that's what you are trying to point out (This is the correct version of the phrase, for how it is used in every case I can think of).

Saying you "could care less", means you do care, at least a little (as Weird Al points out in the "Word Crimes" song). Again, in the places where I hear people use one of these phrases, they always mean they don't care at all, and are trying to emphasize that.

Only "I couldn't care less" makes sense for that meaning.

That's all true, but I would argue that in practice, the colloquial meaning of "I could care less" and "I couldn't care less" have become the same through usage. Much in the same sense as how "literally" came to mean "figuratively" through misuse, to the point that at least some dictionaries now contain an entry for "literally" that refers to the sense here it mean "figuratively". #headexplode

Yeah, I figured that would be mentioned. I just personally don't agree that it's OK to say "well, everyone means 'empty' when they say 'full'".

When the phrase you are using quite literally (hehe) means the opposite of what you mean, that's just abuse of the language. Unless, of course, you are trying to be sarcastic (which is never the case with saying "I could care less").

I feel the same way about literally/figuratively, and at least figuratively (hehe-2) roll my eyes on that one regularly.

Yeah, I hear ya. I'm definitely not happy with the current state of affairs myself. I'd like to think there can be some level of precision in our use of language. But sadly, the rest of the world don't seem to care what you and I think. :-(