Why is it important to learn about yourself?

One word. Predictibility. When you know what you're made up of, what your thoughts are, what your emotions mean, your triggers, flaws and strengths - you can predict how you'd react, thus, having more control over our reactions.

Who we are today is a product of our upbringing, societal expectations, exposure, conditioning etc. When we attempt to strip away all these other layers, we get to the core Self.