People usually crave security and certainty, and go to great lengths to attain it.
The thing is, while there are certainly variables in life one can control, things you know you know, or know you don’t know, there are also those things beyond your information horizon, beyond your control.
My takeaway was that there’s no real certainty in anything, and you can either spend your life trying to attain perfect certainty and never succeed, or revel in the uncertainty, the adventure, the unknown and maybe unknowable. I gave up long ago knowing everything I could know about software development, as the pool of knowledge is immense - and that in and of itself is a joy, to know that I can keep at it, at practically any discipline, software or otherwise, and never stop learning and experiencing novelty.