Double Sided Tape - Don't Come Home Without It
I remember in my earlier days all the times I needed tape thaat was "sticky" on both sides. To accomplish this, I folded a piece of standard Scotch Tape to fasten a bow, label, or other item onto a package . Sometimes, I needed to hold two things together for just a bit, and my folded tape approach often led to poor alignment. I thought at the time, "It would be great if 3M would make a tape that had adhesive on both sides", since my folded aproach had some flaws. It wasn't much longer until 3M released the item of my wishes.
Three cheers for 3M's clairvoyance! Maybe two sided tape influenced Post-it notes, another great 3M item.
