This was a small motion pass, but on mobile those small touches add up.
The bottom nav is persistent, so its feedback has to be restrained. Too much movement makes the app feel toy-like. Too little makes it feel inert.
I kept the press feedback focused on the icon instead of moving the whole tab item. That gives the thumb a response while keeping the navigation structure visually stable.
After a couple rounds, the motion became softer and more confident. It now reads as acknowledgement, not decoration.
That is usually the sweet spot for product motion: enough to make the interface feel alive, not enough to make people think about the animation.