For instance, most people believe that stealing is wrong. However, if you were to take a little boy from the slums of Brazil, he grows up seeing his father stealing just so that he can feed the family. In this little boy's mind, stealing is not wrong, instead its a means of living. This is his reality. Hence, he will keep stealing as he associates it with something positive and no matter what anyone may say, he will always be successful doing it as he believes that that is the only way to survival no matter what he does in life.
We are all different in this way, and we all have our way of critical thinking. The one biggest problem with this mind set (amongst several others) is the judgement that only certain things are possible while others are not.
If we reflect and think, why would some things be impossible to some while it is very possible others? The Answer: Because we believe it can't happen. What we believe we achieve.
Research shows that if you completely believe in something, it is quite likely going to happen. For instance, no matter how many financials problems you are faced with, if you start to believe that you are abundant and financially secure, you absolutely will be. The same applies to weight loss, relationships, family and so forth. You can simply recreate your reality.
Think only positive thoughts and see how it manifests. You can start today by making a list of all the things you want to change in your life and write it on a piece of paper in past tense (as if it's already happened), read it everyday as you believe it and simply watch the magic happen.