If you don't try and you fail, it might be less painful than if you try hard and still fail.
You can think "I could still do it, if I really wanted to." It protects your time, and your ego.
This can become a real problem if you are trying to learn something that can only be done with full mental investment. Mathematics is like this. It requires a kind of intellectual vulnerability.
No one wants to feel stupid. Even just to ourselves.
Math is going to make you feel foolish. It's part of the process.
But if you can follow the reasoning in this rather meandering post, you can probably understand most of the mathematics.
Often students think a problem is hard because it's ingenious and complex when in reality it's just a little tedious.
People who show off at math like to make it seem as if they run on brilliant flashes of insight when it's more about checking for tiny errors, and being systematic.