Most people don’t see the world the way it actually is, but they see the world as they are. Means they see the world through their eyes and the information from the outside world is processed in the brain. Our brain has been evolved and will keep evolving through out our life. This brain evolution is highly dependent on the environment we grew up in and the kind of circumstances we are exposed throughout our life.
We consciously and unconsciously (subconsciously) would have formed various beliefs based on the experiences and our exposure to outside world/people. We value certain things in life and our identity is defined by our values and beliefs. So we see the world through the lens of all these factors which run automatically when we form our opinions and make any decision in life.
Our perception of the external world is highly contaminated and influenced by our internal beliefs, values, thoughts, feelings, emotions, mood.
The world we believe in becomes the world live in. As many philosophers say that the world becomes better when we (our mindset) becomes better.
*Do read the Disclaimer