MP3. I had Winamp running in early 1999, blew people's minds. Had a 2nd Gen iPod too, I remember being told how dumb I was for spending that much on a music player.

Avoiding seed oils and sugar is another. I made the switch 10 years ago. I have maintained a weight loss of 40% over that timeframe, so I think it works.

And now bitcoin! I get a lot of the same feeling from bitcoin & Nostr. It's why I'm so bullish.