Someone posted an old MacOS screenshot on Reddit and it was immediately obvious that the icons without a silhouette were the worst out of all of them.

Like iTunes / Books / App Store. And that's basically what they went with eventually...

Dashboard and Launcher are fine, but they have a reason to be a circle. (Well Launcher less so maybe)

Chrome is terrible, it represents nothing. But I guess it's just a brand.

I wish we could go back to this instead of squircles...

https://www.reddit.com/r/MacOS/s/9MZsGioCG6