Motion as hierarchy
What moves first is what you have decided matters most.
Sequence is emphasis
When several elements arrive, the order in which they appear is a ranking. Staggering by 40 to 60ms makes that ranking legible without anyone consciously registering it.
Move one thing
An interface where everything animates is an interface with no hierarchy of attention. Choose the single element that carries the change and let the rest simply be there.
Motion should explain, not decorate
Good interface motion answers a question: where did this come from, where did it go, what changed. If it answers nothing, it is a delay with styling.
If motion answers no question, it is a delay with styling.
Record a flow in your own product. Play it at quarter speed and write down what each movement is telling the user. Delete anything with a blank line beside it.