I've been collecting movies for my Plex server for a few years, and I went through the phase where I was getting all the classic movies, all the Oscar-nominated movies for every calendar year, etc.
And I stumbled on a movie I would never have watched. But in reading the synopsis for it, I recognized a reference I had picked up as a small child from what was either the very late 1970s or maybe early 1980s. For less than a year (I'd imagine), everyone must have been making jokes about "Turkish prisons". The kind of thing that stand up comedias on Carson would have joked about, SNL, etc. And I overheard one of those jokes (or several), filed it away, and never figured it out.
Midnight Express (1978).
It's funny to me, there have been other such instances. Only took me 40-some years to solve.