Could care less
This saying, like a few others misappropriated by American users, is one that particularly annoys me. It’s not merely because it exists in place of the original and correct saying, it’s because the very words of the saying combine to create the exact opposite meaning!
‘Couldn’t care less’ is a saying used to convey a total lack of caring. Using it demonstrates that the speaker has absolutely no interest in the subject. For instance:
‘Hey, Jane! Simon just broke up with his girlfriend! You know what that means?’
‘Sarah, I couldn’t care less about Simon. He’s a jerk.’
Here, Sarah is trying to provoke Jane into a state of excitement, hinting at the fact that Jane might be interested in the fact that Simon is now single. But Jane replies that she ‘couldn’t care less about Simon’, showing that she has no interest in the topic. However, if you use the mistaken phrase ‘could care less’, Jane goes from someone who has no interest in Simon to someone who does have an interest in Simon and the fact that he is single.
So if you mean to use this phrase in spoken or written English to indicate that you have a total lack of interest in something, someone or a particular situation, use ‘couldn’t care less’.
The only instance you might use ‘could care less’ is when indicating that somebody actually could care a little less about a subject in which they already care a reasonable amount! For instance:
‘Sammy, can you stop fawning over your trading cards? You’re making me feel embarrassed.’
‘Yes, I suppose I could care less about them.’
In this situation, Sammy is admitting that he may have a bit of an obsession and should probably do something about it, i.e. stop fawning over his trading cards. See how different the meanings can be when ‘couldn’t care less’ is misused?
If you want to learn more on this subject, I suggest you check out David Mitchell’s Soapbox Dear America… You will laugh and learn in equal measures.