Most of us were taught that the goal of school is to know things. It is a reasonable goal, but it has a weakness. Facts without reasons are fragile. We memorize them for the test, and a few months later they are gone.
The students who keep what they learn tend to do something different. They ask why.
Why does the quadratic formula work? Why does this sentence need a comma and that one does not? Why did this event happen then and not earlier? A "why" forces the mind to connect a new idea to something it already understands. And a fact that is connected to other facts is much harder to forget than a fact standing alone.
There is a second benefit. A student who knows only the steps can solve only the problems that look like the examples. A student who knows the reason can solve problems nobody has shown them yet. That is the difference between following a recipe and knowing how to cook.
We see this constantly when teaching the SAT. Two students can arrive with the same score. One has memorized rules and panics when a question is worded differently. The other asks what the question is really testing, and recognizes the same idea in a new disguise. The second student improves faster, because every question teaches them something that carries forward.
So how do you build the habit? A few things help. When you finish a problem, ask yourself why the answer works, not only whether it is right. When you get something wrong, ask what you believed that turned out to be false, which is more useful than asking what the correct answer was. And when someone explains something, try to say it back in your own words. If you cannot, you have found exactly where to look next.
Asking why can feel slow at first. It is faster in the long run, because you stop relearning the same things. A curious mind is not a luxury in education. It is the engine.