Regarding I Could Care Less. My theory has always been that at some point, long ago, the phrase was “Like I could care less.” You still hear this variant today. It means the same thing of course, that one could not care less, but the word like makes it clear. Over time, the phrase gets used and repeated and some of the sarcastic intonation drops out, but people still know what the words, in this particular formation, mean. Then the leading word gets lost.

Just pretend it’s really a single word, couldcareless, meaning apathetic. We already pretend that awful means something other than awe full.