The best thing is those fucking sites where after the page seems to be completely loaded suddenly new components or even worse: ads pop in, and you accidentally click on those instead of what you intended to click on.
My favorite is when a full react site loads up, doesn’t have error boundaries, hits some unimportant js exception, and the entire page that was fully rendered and ready to go just pops out of existence and you are looking at a white page. That doesn’t seem like forward progress at all.
If a page is presented, it better be f&@king usable
People like to talk badly about w3schools but at least it manages the bear minimum of actually being able to render and display the information I’m looking for.