Each and every year millions of people wrongly use the term "I could care less". The phrase "I could care less" has become a very common phrase used to express your lack of interest in an aforementioned topic. However, the phrase makes no sense. We, the people of the internet, must fix this!
Now, by using the phrase "I could care less," the point you are trying to make is, on a scale of 0 - 10, that you care absolutely 0. However, if you could care less, you cannot be at 0 caring, as there must be a level below that to care less.
Now, the correct phrase to express 0 caring is "I couldn't care less." If you could not care less, then you are Absolute 0 Caring. You CAN NOT care less than you currently do. Absolute Zero Caring.
tl;dr
I could care less : WRONGI couldn't care less: RIGHT