Great API design matters
SpaceX docks the Crew Dragon spaceship to the International Space Station after a 19-hours journey since it lifted off from NASA’s Kennedy Space Center in Florida. Great achievement as a result of lots of smart work. Imagine getting all the way up there to realise the interface has changed and it won’t dock. It would be too late to blame requirements, design, dev and/or test. And another iteration would come with an expensive price tag.