Core Web Vitals are unforgiving

You can have a site that scores 100 on PageSpeed, but not pass Core Web Vitals. Using Daring Fireball as
an example, here is how it ranks:

I was totally taken aback by this. This is a good LCP. CLS is perfect. Even so, a quarter-second FID (First
Input Delay) score is enough to cause an otherwise perfect page to fail. Quite impressive.