Animations
Every project has one interaction that cannot be settled in a static frame. Arguing about it in review is wasted time, so I build the roughest possible version of it before anything else gets refined.
Homepage animations
On the homepage that was the glow behind the hero. A still frame makes it look decorative; in motion it sets the tempo for the rest of the page, which changed how much the type needed to do.
Product hero animations
Product heroes get the same treatment at a smaller scale. If the motion only works at full width, it is a layout, not a behaviour, and it will break the first time someone reuses it.
Prototype first, then decide what it costs. Usually the answer is less than the meeting would have.