Almost everyone knows about the famous line from Gone With The Wind, when Clark Gable says to Vivien Leigh, "Frankly My Dear, I don't give a damn".
But is that actually correct? Shouldn't it be "I don't give a dam"? The whole "I don't give a dam" phrase came from the Indian coin called a "Dam". So by saying something wasn't worth a "Dam" you were literally saying something wasn't worth the inexpensive indian coin.
I don't know if "I don't give a damn" even makes sense. There isn't a definition that properly fits the quote.
It might sound like a silly thing to debate. But me and my employee were talking about phrases that people fuck up all the time. I mentioned this and we debated it for a bit till I showed her there was a real thing called a "Dam". She then brought up the Gone With The Wind quote.