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

Being able to look up and verify just about any fact in seconds via a magical device that fits in your pocket and only needs to be charged once a day, then never using it to do that.

Yes! I dunno if it’s still reasonably possible, but I remember downloading a text copy of Wikipedia and thinking how cool that was. And earlier than that, back in the CD-ROM era (90s), digital encyclopedias were actually an exciting use of the technology and I was given one as a Christmas gift.