I really like the german "Geburtstagskind". It refers to a Person whose birthday is today but literally translates to "birthday child". However you use it for any age. If its your grandfathers 80st birthday he still is the birthday child this day. Usually people just use the word without thinking about it , but i really like the idea that everyone can get childish again on their birthday. :)
"Lukee kuin piru Raamattua" (Finnish).
Literally "to read like the Devil reads the Bible".
Meaning to examine something in bad faith. Never heard it used it in context of the Bible or anything religious, but eg. when interpreting law or contract, looking for the details that could be twisted for your purpose, rather than what the text attempts to convey.
Here's one in Egyptian Arabic: "He who gets burnt by soup will blow on yoghurt", meaning that someone who gets hurt once will bexome careful not to repeat the experience.
In colloquial English, you can say that someone is an idiot with the construction "you absolute [noun]" or "you complete [noun]" or similar.
It doesn't actually matter what the noun is, but it works better the more obscure or specific the thing is. For example "you absolute saucepan", "you complete hose pipe", or my personal favourite "you absolute strawberry plant".
One of my favorite youtubers Octavius King demonstrates this really well by using "complete and utter desk" as a derogatory term for the worst offenders to intellect.
An example as if I was talking to you: "I'll wack you like an octopus" which technically already describes the action, however traditionally in my country after catching octopus in order to properly kill them and soften them up, fishermen basically smack/wacked them on the ground maniacally.
And I think it's become such a popular figure of speech because that mental image is hilarious and I love using it.
"Butt fuck Egypt (BFE)," when referring to being in the middle of nowhere or the far edges of a parking area.
For example, Sally complained to her friend in the food court, "I had to park all the way in BFE. I'm dreading the walk back to the car."
That's actually quite an interestingly accurate one, considering that something like 95% of Egyptians live near the Nile River, and anywhere that is NOT near the Nile is desert wasteland.
Other accurate analogies would be anywhere in Canada that is NOT near its' southern border, or nearly anywhere/everywhere in inland Australia, they call it the Outback for a reason.
I don't speak German, but I picked up a few phrases for work. They have a few idioms that I think of sometimes:
"Ich glaub, ich spinne" which means I think I'm crazy, but literally translates to "I think, I spider." It's a great visual metaphor, being overwhelmed by the threads going everywhere that you imagine you're a spider spinning a web, and also you've entirely forgotten grammar.
"Bahnhof verstehen" or "Ich verstehe nur Bahnhof" means "I understand only the train station." It's something you say when you don't understand anything, you're completely lost, and you don't give a shit becaue you just want to get the fuck home.
I might be off on those translations or the subtext, but that's how I understood it.
The "Bahnhof verstehen" comes from the notion that many people learning a foreign language start with some simple sentences like "Can you tell me the way to the train station". So people who only "Bahnhof verstehen" (OK, horrible grammar here) have not proceed past the first lesson.
"Correo de las brujas" translates to "the witches' mail" and means gossip or rumors. Kind of like "heard it through the grapevine" or a "a little birdie told me"