See also https://bintanvictor.wordpress.com/2017/05/29/transparentsemi-transparentopaque-languages/
I was technically very, very confident in my 20’s to early 30’s until I was bogged down in some tough projects. I think many successful and competent techies experience the same at least once in their career. They though they were powerful, invincible but then a tough project was given to them that they struggled to get done. Later someone else got it done without much effort. (For a public domain example, look at the kernel project in GNU.)
It can be harmful to dive so deep into past personal limitations but then a hard, honest review could be life-enhancing. I see myself as a tough grown-up guy so I can take the pain.
Eg: GS rule-engine re-architecture in 2007 — too early
eg: see the opacity issues in https://bintanvictor.wordpress.com/2017/06/12/xp-3typestech-zbs-challenges/