I remember when they were showing us the future in the form of CDs. The were all glistening and shone brightly and you could have a stampede of rhinos trample all over them, drive a bulldozer over them, scratch them with a carving knife and lo and behold, they would still be perfect and play perfectly. What they failed to tell us was that if you dared to get so much as a teensy weensy little smudge fingerprint on them , they would skate around all over the place and never play properly again.
Also, Back To The Future 11 was set in 2015 and there are all sorts of flying cars etc in that. Well, 2015 is only 6 weeks away. I still haven't seen any flying cars or sky highways.