I'm so exhausted these past couple of days, and I suddenly had a realization:

People's ways of thinking are really different.
Take learning from a book as an example.
Student A's perspective: A dotted line—although he studies every chapter and can master the knowledge points, even recite them backwards, if questions are based on a few chapters' knowledge points, he might not do well.
Student B's perspective: A straight line—he studies every chapter, and whether the questions are based on single or multiple chapters' knowledge points, he can handle them.
Student C's perspective: A ray shooting out from a point in all directions, with some rays connected by lines, like an infinitely large "badminton shuttlecock." Not only does he learn from this book, but he also studies many other books in unseen times, makes inferences, sees connections, and learns quickly.
Through continuous accumulation, all three can become so-called teachers—either through books or videos, or face-to-face classes—sharing what they've learned with others.
Student A corresponds to: the dotted line teacher.
Student B corresponds to: the straight line teacher.
Student C corresponds to: the badminton shuttlecock teacher.
What I want to say is: if you're Student A, when you learn knowledge, you can look for the dotted line teacher and the dotted line teaching materials—not meaning to learn the dotted line itself, but focusing on a single skill. For example, if you're learning trading, trading has many systems. You should choose one system and master a small trick within it that can make you money. Master one trick, and you can succeed with it. You won't learn everything else.
As for Student B, you can learn an entire system thoroughly and specialize in it, becoming a dedicated system trader.
And Student C, learns all systems, makes connections, and eventually becomes versatile—known as a trading genius, someone who can write books and leave a mark in history.
Many of us correspond to different ways of thinking, and different ways of thinking lead to different learning styles. If you don't find the right method, problems often arise. For example:
Many people I meet understand all systems but just can't make money. This might be because they adopt Student C's learning style with Student A or B's perspective.
I deeply feel: I belong to the dotted line (A) perspective. If you give me a book written by a Student C, I might not understand what he's saying because his book is probably like a gazelle hanging on a horn—first chapter covers this (the concept will be explained later), tenth chapter (wasn't the fifth chapter already covered? I won't go over it again; if I don't understand, I need to review). I would be confused. If every chapter is just 1 equals 1, 2 equals 2, without explaining addition, subtraction, multiplication, or division, then once I learn 1, I can master 1. For example, farming: the first chapter is about land cultivation—regardless of soil type, fertilizer, season, or method—everything about land cultivation is in the first chapter. No need to mention other chapters. Once I finish the first chapter, I will definitely master land cultivation.
Or, to put it another way: even if he's a Student C, when teaching others, he has to use methods from A or B, or he doesn't realize his students are all A or B types; he thinks they're all like him—C.
So sometimes, it's not that you're stupid, but that you haven't found the right method or the right teacher or teaching materials suited to your thinking style. Otherwise, your efforts will be less effective.