This is not “Back to the Future Day.” Someone cleverly photoshopped the date on a screen grab, just as was done two years ago. And that date isn’t even the one they travel to in Back to the Future II, it’s just the date that Doc Brown sets as an example when showing Marty the controls near the beginning of the first movie. The Back to the Future II date is October 21, 2015. So we still have to wait three years (and change) for our hoverboards, rehydrators, Jaws 19, and the inability of anyone to notice someone hiding just half a foot behind them.
Also in the realm of common myths: people do not use only 10% of their brains. That old common piece of wisdom came from a misinterpretation of late 19th century neurological research. Perhaps the idea keeps getting repeated because most people would be rather terrified to learn that, yes, this is what they’re like using their whole brain.
I seem to have missed the part of my lease where it says that all dogs must bark loudly and ferociously as if attempting to attack a fiery demon from the pits of hell whenever they are being walked through the halls, day or night, and that their owners are forbidden from saying or doing anything to mitigate this cacophony.