This is a detail, but it's imo illustrative of how refined Apple UI is and how easy it is to get it wrong.
The design of how the Dock scales and animates follows a very simple principle: if the mouse is outside the dock, and you move towards an icon vertically, entering the dock does not shift that icon around. Because that would make it feel "jello" and uneasy, like this imitation.
The design of how the Dock scales and animates follows a very simple principle: if the mouse is outside the dock, and you move towards an icon vertically, entering the dock does not shift that icon around. Because that would make it feel "jello" and uneasy, like this imitation.