Sometimes people make something happen because they believe it will happen so strongly, but are totally unaware of it. When this happens it becomes a psychological problem. ;-)
The thoughts we dwell on, be they positive or negative, have a direct impact on our actions.
When we allow negativity to overcome common sense, believing the worst will happen even when there is nothing to suggest such forces you into playing the role of victim. Literally, you sending your thoughts out into the universe as if this negativity is more important than anything else.
Eventually, you will create the very thing you dread, which becomes a self-fulfilling prophecy.
However, when you are convinced that you will succeed, no matter what comes your way, the vibrations you are sending out into the universe are positive. Positive energy attracts positive events, positive people and success is much easier when you are focusing on positive energy.
When success does come, it is also a self-fulfilling prophecy.
Psychologically, speaking, we create our own lives from the bottom up, and the choice is always right in front of you. The challenge lies in recognizing problems as opportunities to prove yourself a winner, no matter what happens.