I know the Leopard era design is having a bit of a retro cool moment right now (frutiger aero) but for me its all about that pre-Leopard Aqua. Something very bright and friendly about that design language where the Leopard era feels a bit dark, moody, and dusky. Bordering on chiaroscuro. Especially when you compare classic Aqua to like the classic Windows look which while coming off as corporate felt like it had a precision to it (at least to my kid brain).
I have to say my hot take is that I actually kinda like Liquid Glass. It feels like a bit of a throwback to that era and dragging objects behind transparency to see the refraction was the first time in a long time I've ever just been transfixed with just playing with a UI detail. Especially since I use the Dock as bootleg taskbar (undock everything so the only things in it are the open applications and autohide), when it does pop up its fun to see everything bend around.