I'm regularly surprised† that many people have such a revelation by themselves when it's one of the most basic ways of forming knowledge and progressing towards understanding and solving problems:
> Le second [précepte], de diviser chacune des difficultés que j'examinerais, en autant de parcelles qu'il se pourrait, et qu'il serait requis pour les mieux résoudre.
> The second principle, to divide each problem I examine, in as much fragments as possible, and as required to best solve them.
— Descartes, Discours de la méthode, 1637
† "Aghast" would be a better term. My surprise is not so much aimed at people as at an education system that fails both at making people stand on the shoulders of giants and at making them able to reason on their own.