What’s something you remember vividly – but if you told a younger person they would not understand?

I was recently trying to explain what a mixtape was to my friend’s teenage daughter.  She likened it to a Spotify playlist.  She’s on the right track…kind of…but

you had to physically record your mix on to a cassette.  There was also the possibility it could wear out or (god forbid) your player might eat the tape. If it wasn’t too bad you could wind it back in with a pencil.

So many variables!

But I might as well have been speaking a foreign language…she looked at me like I was nuts (when she wasn’t looking at her phone).

What else could you tell a younger person – that they would not understand?

Please share.