When Marty wanders into the 2015-version of Lou’s Diner, he finds it full of styles and pop culture from the eighties. Doc Brown even calls it “one of those nostalgia places.” Michael Jackson is playing, popular television shows from the eighties cover a wall, etc..
There’s even a reference to what Lou’s Diner used to be in the eighties version of Hill Valley since in the 2015 version there’s an aerobic exercise machine stuck in the corner. In the first film, Marty swings past the location as it’s full of women following the aerobic craze of the eighties.
A Long-Running Series
"Back to the Future II" is set in the distant future of 2015. Things didn't exactly match up to what the filmmakers had envisioned, but they probably don't care. There's no hoverboard, and there's no way the "Jaws" franchise got nineteen movies.
The huge hologram that sprang out of the movie theater was inspired by the incredible number of sequels "Jaws" spawned in such a short time – four had already come out by the time of "Back to the Future Part II". After that, however, the series pretty much tanked, and not even Steven Spielberg's son (“Max” in the movie) is interested in resurrecting it.
Are You Sure These are Antiques?
When Marty lands in 2015, to say it's a culture shock is a little bit of an understatement. He wanders past an antique store, where he finds the sports almanac, and the store is jam-packed full of things from his era – a 1984 Macintosh computer, NES games, and even a Roger Rabbit doll.
Interestingly "Who Framed Roger Rabbit?" was the film Zemeckis directed right after "Back to the Future". There are plenty of other items in the antique shop (including a copy of the "Jaws" book) which were commonplace in the 1980s, and even now you might have some of it still in use.
Just a Year Off
As Marty wanders through the distant future of 2015, he comes across a billboard or advertisement telling him all about the champion Cubs, who have just won the World Series!
This is of course a reference – and joke – about how the Cubs hadn't won the Series for eighty-two years, even when the movie came out in 1989. They even beat a Miami team, which didn't exist. A Miami team does now exist – the Miami Marlins, begun in 2012, and the Cubs would win the World Series in 2016, just a year after the movie was set.
His Shirt Tells the Future
In 2015, Hawaiian shirts are IN. Doc Brown fits in like a charm, throwing on clothes that stand out and blend in just right. However, looking closely tells us that the filmmakers were planning for the third installment of the series while even filming.
The pattern is quite significant. It seems to be a group of men on horseback chasing after a speeding train. While that's a relatively normal Western scene, it's also foreshadowing for what happens in "Back to the Future Part III". It's known that the filmmakers worked on "Part II" and "Part III" at the same time, so this seems quite on purpose.