What is something that's crazier than the wildest dreams of any ~1970s nerd, but exists today? I'll start with an easy one:

4TB??. I remember being in highschool in 2003 and we were all standing around looking at a 1GB USB. It was insane that a USB could hold an insane 1GB

My first MP3 player was a USB stick that plugged into an adaptor that had a 3.5mm headphone jack… It let me carry 60-85 songs, There was no Bluetooth.