One of my favorite coaches, Michael Neill, writes of an insight that he thinks is so fundamental that people cannot make significant progress until they see it.
That insight is that our world is literally made of up thoughts. We do not think about our world. Instead, we think our world into existence.
Almost everything that we think of is an interpretation of something, or a labeling of something, or a conceptualization of something or an evaluation of something. And those somethings that we create and interpret include events, people, and every our very sense of self.
We take our pure experiences, which are beyond language, and use language to categorize them and file them away. And then, we use them as evidence that the world is the way we think it is.
Until we see the way that we do this, we have no hope of making fundamental change. But when we do see it, it is almost impossible not to change.