I could care less if you read this
Your ex has just posted a way snarky comment about you on MySpace. “Hah!” you type madly on your profile, “I could care less!”
You could? If you could care less, then that means you do care, because you are capable of caring less than you do now. After reading your response, your ex is undoubtedly smiling in that self-satisfied way that you despise.
If, however, you fire off a comment proclaiming “Listen, loser, I couldn’t care less,” then you’ve expressed your true feelings. You are incapable of caring less. The matter means nothing to you; you don’t care about it at all. Let’s just see if the one-who-must-not-be-named cares about that.