If you say, you COULD care less, it means that you DO care some...
when you want to say you DON'T CARE about something, you should say I COULD NOT care less...
let's say we measure our level of CARE on a scale from 0 to 100.
If you don't care about something, your care level is 0, so you COULD NOT care any less!
If you say you COULD care less, then you obviously CARE...
