You piqued my interest - in what language is the literal translation of "dickhead" not insulting? And what does it imply in that language?

In the UK words like that can also equally be used as terms of endearment amongst friends... context is everything.

I don't think that's a UK thing, but rather just a close friends thing, which I experienced across multiple cultures. I recall a particular incident as a kid when my dad forcefully told me "Don't talk to me like that; I'm not your friend" and that stuck with me - you need to adapt your tone to the audience.

The last thing I expected was to get downvoted for just saying "English language can be a landmine if you are not careful, especially as a foreigner! lol".

English language uses words such as pussy that supposedly mean a cat, but at the same time they interpret it as vagina; another word is the name Dick which also is being used to mean phallus!

...and the best one is spotted dick which is literally a British steamed pudding! https://en.wikipedia.org/wiki/Spotted_dick

Meanwhile, I get downvoted for commenting the obvious thing which is, English language is absurdly confusing for me as a foreigner and have no idea what to say without offending every English speaker!