I started web stuff in the 90s as a child. I didn't know what CSS or JS were, except the latter you could copy/paste some magic scripts to make things flash and suchlike. Later I built dynamic sites with PHP for local businesses. I learnt JS and CSS at this point (to some extent as least). Then I decided to quit web development because I couldn't stand spending so much time things to work with the shittiest browser available (IE6).

After almost 6 years away I came back around 2015 when I realised a web server would be useful for whatever I was doing. I was shocked to find the world had forgotten about so much regarding HTML and CSS. We used to build multiple stylesheets for our sites. That was forgotten. We used to make stuff work without JS first, then add JS as a nice-to-have afterwards. That was forgotten. I saw web devs just doing all their form validation in js and the server doing none. Shockingly, this is still common today. I'm not aware of a common pattern where you get the server to do validation and just display it in js. Everyone seems to either duplicate or not even do it on the server at all!

When I saw this I was no longer impressed by what people were doing on the web because it wasn't the web I knew, it was just "applications" built in JS. Trying to argue for "web first" was a losing battle.