I was the master of mix tapes and continued the tradition right up to college (before making mix MP3 playlists, CDs and minidiscs).
I took to a blank tape like a painter to a blank canvas. Every little second of room on the tape would be filled, thought having the end of your song cut off was a pain in the neck but it didn’t matter – flip the tape over and it was game on all over again. I’m sure I’ve still got a 1997 Radiohead recording from a 2FM Live set (possibly Glastonbury), some cheesy dance mixes from 1995, some worse dance mixes from 1992 (I was all of 9 years old) and it goes back further.
It set me on the road to ruin and a fascination with audio so I’ll happily claim the blank tape as one of my favourite inventions (or my favourite) from my childhood. All that BASF and TDK or Memorex chromey goodness.