I’ve come to realize that what I hate the most about rounded corners isn’t their roundness (even though it’s ugly), but their lack of information density.

When everything is inside its own card with huge rounded corners, and every button is rounded, and every icon is also rounded, you end up wasting so much space. UIs feel clunky and really slow to navigate, and you have to obscure things behind more buttons because they don’t fit.

On the contrary, sharp corners fit a lot better on a UI, and they’re usually closely related with dense interfaces. I love dense interfaces, because I’ve come here to use the software efficiently, not have something esthetically pleasing but poorly functional.

As a side note, you can edit firefox’s userChrome.css and get your squarer corners back. I haven’t yet tried this on the new firefox, but I do use this snippet on all my computers, after mozilla rounded the corners more in a previous iteration of the UI.