The cause of misery on the planet

All the misery on the planet arises due to a personalized sense of "me" or "us." That covers up the essence of who you are. When you are unaware of that inner essence, in the end you always create misery. It's as simple as that. When you don't know who you are, you create a mind-made self as a substitute for your beautiful divine being and cling to that fearful and needy self.
Protecting and enhancing that false sense of self then becomes your primary motivating force.

Eckhart Tolle