In three years, 1985 will be as far away from me as 1955 was to Back to the Future's original audience. That means that I behold the 80s aesthetic the same way that Marty and his audience beheld the 50s. When Back to the Future was being made, special effort was put into the set design, the costumes, the dialog, the mannerisms, and the cultural references to really bring out the 50s atmosphere during that portion of the movie.
But no effort was put into the parts of the movie set in 1985. The clothes, the music, the dialog, the general atmosphere was just how it was. When Marty says "heavy" and rides a skateboard, it's not because the story is set in 1985. It's because that was just life when the movie was made. So while trying to resurrect the 50s for film, Back to the Future accidentally time-capsules life in 1985.
So, to me, Back to the Future feels like a split period study. As a viewer, I am examining the contrast between 1955 and 1985 differently because A) they both feel synthetic and B) Because I'm going to be comparing the movie to 2015. Back to the Future is as much an 80s study as a 50s study, and it became so by accident.
