The way some people used to make entire websites as flash apps that would bring old computers to their knees is not something I miss. Websites that should have just been static html, like a restaurant's website for their menu, were getting turned into monstrously inefficient interactive nightmares that wouldn't even load at all if you didn't have flash (which btw, broke constantly with Linux.)
This kind of superfluous interactivity is still possible with javascript/etc, but it seems to be less popular and is more likely to gracefully degrade (usually the relevant content still displays even if you have JS disabled.)