For me it was a video of a big fat Hawaiian guy in a pool or something, I saw it for years, hundreds of time, in my "recommended feed". I now know this is a singer, Israel, but I never ever clicked on the thumbnail, and it always came in my feed, I never knew why, after a few years it disappeared I guess the algorithm has a limit of 2000 print per user or something? At one time it said "ok, this user will not watch it, let's bother someone else for middle-aged healthy ad" ?