A person can fail at anything. A job advancement, a diet, a relationship, a new business. While the outside world can certainly be an influence to your success or failure, the ultimate responsibility resides within you.
Many people don't realize this, or simple refuse to accept it as a possibility. They feel that things happen to them, and they can't do anything about it. They blame the economy, other people, their parents, their husband, the weather, the price of coffee in Columbia, the mechanic, the school system, the government, bad luck, or the family dog.
Anyone but themselves. And until the person can accept responsibility for creating their own life and circumstances, and work to change things in their favor, they will continue to set themselves up for failure.
Say you lose your job. You don't have much in savings. But you have the mortgage to pay, the water bill, your daughter needs braces. You're health insurance will be discontinues in a couple months. You're having real trouble finding a new job that will be able to pay your bills because the economy is bad, and no one's hiring.
How do you react? The person who sets themselves up for failure will immediately feel a great deal of stress. They will feel hopeless, and perhaps anger towards a number of different entities, perhaps at his ex-boss, the government for creating the poor economy situation, the world in general. He'll start throwing around blame towards other people and circumstances that put him in this situation. He may get a lower-paying job to pay the bills, and maybe even two.
What about the person who isn't prone to setting themselves up for failure? If he is in the same exact situation (which isn't likely, because he will probably have planned for such situations beforehand, and has a good emergency fund and other resources already in place) he will most likely think and act in a completely different manner. He will be upset and worried too, but will use his energy to fix the situation as soon as possible. He might take the low-paying jobs, but will actively seek better opportunities. He will probably think about what he did wrong, and figure out a way to prevent those things from happening again in the future. He might work to build up his savings, or take college courses to improve his career opportunities.
Failure isn't the result of bad luck. It isn't the result of circumstances not in your favor. The person who succeeds does so because their mind is set on success, not failure. Once you get it in your mind that something can't be done, or things will never change for you, or that you are just unlucky, then that's what's going to happen.