Grammar Nazi

I always find it odd when people say that they "could care less". It's supposed to be "couldn't care less" to denote that a person is so unconcerned with whatever or whomever is the topic of their disdain that they are at the absolute bottom of their caring meter. By stating that you "could care less" you are asserting (incorrectly, I presume) that there is indeed the possibility of caring less than you care now, and does nothing to provide a point of reference for the listener. If you "could care less" then obviously you care somewhat. And if you care at least somewhat, then how much? And is it a lot or a little? Is it a reasonable amount, or a microscopic bit? Your (presumably incorrect) statement leaves me nothing to measure. I just don't get it!

Which leads me to the odd threat of "fixing your wagon"...