Your beliefs don't change reality. Reality is whatever it is, no matter how many idiots believe or want it to be some other way.
But your beliefs can distort your perceptions & change your actions. And your actions can change the conditions of reality within your locus of control.
If you look for opportunities you will find opportunities. If you look for obstacles you will find obstacles. And the ability to find what you are looking for will grow & develop like a muscle. One will serve you & the other will destroy you.