Do you believe in karma? What does a belief mean? When we have beliefs they change the way in which we see things.
Believe the world is a wonderful place and you will see more beauty, believe it is a horrible place and you will see more misery.
Beliefs are something that sometimes we don't even choose, or know how we got them. However once we realise that we have them then we have the choice to change them.
The big question is are the beliefs we hold serving us or not?