“Lives rent-free in my head” is a horrible cliche. By now, it has the same effect as saying “it’s nice” but uses lots more letters.
Let people enjoy things.
Doesn't seem to be what the author meant in this case.
It works when there's something that is problematic for taking up space in your head. It colors the way you think in a way you wish was not the case.
While I could strain and make that sort of make sense here (eg it uses up some capacity that would otherwise allow the author to remember other more immediately useful algorithms), it's clear from the article that the author only means "I still remember the CORDIC algorithm" and nothing more.
Not a big deal, but it momentarily annoyed me as a "clickbait and switch" headline.
living rent free generally means that you are able to easily recall a piece of knowledge (and often do, even if you don't want to).
something that pays rent might be like an important concept for an upcoming school test, for a class you're not interested in.
The term in its original use described an obsession with a particular group or thing and called it out as pointless. I don't think it would make sense for rent to mean effort in this original sense, nor in the broader way it's used here.
In addition, it literally says "rent free". There's nothing intellectual or pseudo-intellectual about reading the phrase "rent free" and concluding that the information does not pay anything to live in your head. This is basic reading comprehension.
Get a hobby.
Yes it is, much like "dumpster fire" or "toxic" or "gaslighting" or any other contemporary Reddit-isms that are associated with hyper-reductionist cultural hot takes. My personal distaste for them, however, has no bearing on the fact that they have very real meaning and people enjoy using them.
> By now, it has the same effect as saying “it’s nice” but uses lots more letters.
The commonly-held meaning of this is that it describes a pervasive, intrusive thought, not a nice one. This particular turn of phrase is often used to describe how politicians devote energy to talking about other politicians that they don't like, for instance.
Hey it's a quine, too!