The practice of zazen that we do today has developed out of the teaching and experience of Buddha. It leads to an experiential understanding of our true self. Many people begin to practice because they want to find peace of mind or a way out of suffering, and these are sufficient and legitimate motives for beginning. Although zazen demands discipline, if you persevere, you will find that it will, indeed, help bring more simplicity and peace in your life.
Pursue it long enough, though, and you may be surprised to find that ultimately the practice of zazen totally upsets your familiar worldview and idea of yourself. It does not simply offer a bit of solace to help make life easier. When faithfully pursued, it radically cuts through our present understanding of ourselves and of life. It leads to the experience of what is Real and to deep joy and peace. Zen practice clarifies the jewel of our existence.