Story time!
So I am a Professional Web Developer
and I got stuck on a bug yesterday that it took me and another Professional Web Developer
(with something like 14 years experience) about 3 hours to diagnose and fix yesterday.
It was stupid simple: setState in React to dismiss a modal. Absolute bread-and-butter stuff.
But we got there - after much head scratching and gnashing of teeth.
You can read my postmortem with a couple of CodePen reproductions of the problem and the fix here, if you are interested: https://jacksonbates.github.io/blog/setState-fail