My crowning glory for the interview-stupids was relatively early in my career going in for a PHP interview, which was the language I was by far the most familiar with at the time and had written many thousands of lines in, and not being able to come up with the "->" syntax for method invocation & property access when I was up at the whiteboard. I used a dot-style instead, and realized only after I left that I'd totally fucked it up (writing some OO code on the whiteboard was just about the first thing they asked me to do, and the interview was really short after that...) I'm pretty sure I also mis-named some built in functions. I'm bad at retaining language-specific details and have since started reviewing a relevant language syntax minutes before an interview, which won't stick by the next day but usually does for a couple hours so I don't do anything too embarrassing. Not being able to put together two non-syntax-erroring lines in a language I wrote a few hundred useful lines of the day before, without a reference, is otherwise the norm for me. This has mattered zero times—except in interviews.

Do you want me to write fizzbuzz in proper syntax in some language I have on my resume and 'can do' but don't actually do every day without the help of an IDE? Forget it.

Can I write pseudo code that doesn't compile, is an amalgamation of various languages and probably understandable by anyone that can code even though there's probably no language w/ that syntax out there but it get the idea across perfectly? Sure!

    foreach (number in numbersYouWantMeToFizzBuzz) {
        if(number MOD 15 eq 0) print fizzbuzz
        else if(number MOD 3 eq 0) print fizz
        else if(number MOD 5 eq 0) print buzz
        else print number
    }

Don't have the {}? Who cares, you might be a python guy. Don't have the indentation? Meh you pass but my next question will be about formatting and what you think about applying a standard code style (and fail PRs automatically if it doesn't etc). You used % because your language uses that for MOD? Sure.