People do hard things and go through hard times simply because they have to. Uninvited troubles and problems can be just as powerful as the ones we choose for ourselves. Life is such that there are plenty of challenges and problems to go around, even if we don't choose them. Choosing our problems and deadlines presupposes that we know ourselves - what we enjoy, what our talents are, what we want out of life, and that we have a reasonable amount of freedom to act on our choices. Goals bring focus to one's energies.
Decisions are easier when goals are defined.
Clear-cut goals make it easier to recognize opportunities and to spot problems when they occur. Part of life is to undertake this journey of self-discovery without having the destination fully in mind, and then having the courage to define, revise, and refine our goals as our vision grows clearer. Obstacles force a greater vision and demand creative solutions. As we create, we grow. Life isn't a straight path.