Personal rules for "bad" language

I recently came across this article:

 https://www.italki.com/article/1229/7-Spanish-Slang-Words-From-Netflix-Show-Club-de-Cuervos

Which uses (and therefore teaches) swear words.The English translations are censored, but the Spanish (the language being taught in the article) are not.

I thought it was an unwritten rule, that you don't teach adult language (+slang) to beginners/intermediates.

It made me think about my own rules for learning/teaching "bad" words.

I would never teach swear words to a beginner who is interested in becoming fluent in my language.

But if you are not interested in learning and actually communicating in the language and are only curious about having fun, then I can teach you some funny adult language (I'm talking about foreign friends in real life, not here on Italki).

As for learning...

I avoid bad words, after unknowingly swearing in German when I was in elementary school (After watching too many episodes of "Cobra 11" (German police drama) instead of saying "Leise" I said.......something else).

What is your opinion on the matter?

Idioms:a faster way to get your point across. today: it's easy

Idioms: a group of words established by usage as having a meaning not deducible from those of the individual words.

Today's idiom: "It's not rocket science".

Meaning: It is not complicated= it's easy.

Origin: After the second world war, German scientists were sent to the USA to have a leading role in "The Space Race". Their work ("rocket science") was regarded as requiring an above average level of intelligence. In the beginning, the idiom was often used in regards to football.

Quote from The daily intelligencer <a href="tel:1985">(1985</a>.): "Coaching football is not rocket science and it's not brain surgery. It's a game, nothing more."

How common is it?: highly common.

Idioms:a faster way to get your point across. today: luck Idioms: a group of words established by usage as having a meaning not deducible from those of the individual words.

Today's idiom: "Break a leg".

Meaning: Good luck.

Origin: Theater (performers would sarcastically say                  that to eachother before going on stage).

How common is it?: Highly common.

A favourite word in your new language. I was thinking about how much I like the Russian word "Снова" (meaning: "Again"), the reason being that growing up I remember hearing it only in fairytales or poems in Croatian ("Snova").

And in Croatian, "Snova" has a homonym, which means dreams.

But for Russian speakers it is a very common word.

So I was wondering...have any of you learned a word  that you like very much, but it is just a very regular word for native speakers?