"I could care less"
A phrase used (incorrectly) by people when what they actually mean is "I couldn't care less"
Say there is thread on, oh I don't know, forum renown and that thread does not interest you in the slightest, you don't care.
When you reply with "I could care less" all you are doing is demonstrating that you actually do care in some way. Even if it's only a little bit, because there is an amount lower than what you currently care.
What you actually mean is the opposite, that you don't care, you could not care less. The opposite I might add, is the only indicator of how you're feeling excluded by telling us you could care less.
"I couldn't care less"
Much better.
In before "I could care less about this thread." Obvious. You'll have to do better, probably by critiquing the grammar in the rest of my post because my logic is flawless.
Thanks for reading.