I noticed one day that I use a lot of metaphorical expressions picked up over the years (mostly as a child from family) whose origin I haven't any idea about. I know what I mean, others know what I mean, but I don't know what they mean in a literal sense. But I learned them so young, and they're so ingrained in my vocabulary, that only occasional do I have the self-awareness to catch myself using one. When I do, I start to wonder what on earth I'm talking about.
For example: "A fly in the ointment." I use it to mean "a minor problem that could have big effects," but I don't know how it got coined. Others usually understand what I mean (probably because most of them grew up in the same geographical area and heard the same expressions). But nobody ever says, "What ointment?" Did people use a lot of ointment in the past, and were flies a problem? Were flies NOT a problem, so when one appeared it was worth remarking on?
"Spanner in the works" is related, but I can guess what that means, given that a spanner is an English wrench, and a common American expression is to sabotage something by throwing a monkey wrench into the machine. Both are only barely metaphorical, as their meaning is clear, and I haven't bothered to look them up.
I've always meant to make a list of these expressions, but now that there's Google, if I think of one I just look it up. (Which is how I know what "the whole nine yards" means. It's a reference to an ammo belt on the guns in U.S. bombers in World War II, and if you used the whole nine yards, it meant you were fighting the whole way there and back. For years I assumed it had to do with football.)
For the record, I looked up "fly in the ointment" as I was posting this. It's likely from the King James Bible, saith Wiki, from a phrase where a fly got into the ointment from an apothecary, causing it to spoil. Small problem, big effects, as I thought. But I should have guessed "Bible" from "ointment," since that's about the only place I run across that word. Anyway, now I know.
A third example is "another precinct heard from." I know it means yet another voice piping up in a conversation/argument/debate, but I never knew whether the precinct referred to elections or police headquarters. Turns out, the original phrase is "another county heard from," and "country" is sometimes heard as well, But it comes from the 1800s and does refer to elections.
But whether I know the meaning or not, I continue to use these archaic expressions. So I'm curious if y'all have any examples of these, whether you've looked up the meanings or not.
When I think of "weird expressions" I think of Negan and Eugene from The Walking Dead.
Of course, I can't think of any off the top of my head, but I'm sure there's a list online.
This site provides the sources of expressions coined in movies.
The ones in the (terrific) movie Heathers were intentionally coined by either the writer or the director. It was because using existing slang terms/phrases would date the film almost immediately. Some (such as the use of the word "much") have come into real-world use.
The expression of someone or something being "toast" comes from Ghostbusters.