Zero-knowledge proofs are a way to prove that you know something without revealing what it is.
When I got to 40 or so... I had the sense when I looked back over my life I would actually see a mess of decisions, a few of which I had thought about, some of which I had sort of stumbled on, and many that I had no control over whatsoever.
Contemplating the weaknesses of others is easy; contemplating the weaknesses in yourself is hard, but it pays a much higher reward.