Each piece of crystals is a unique individual like us. They working better with certain pieces and less efficient some others. And even for round shape ones like crystal beads, all crystals do have a directions of energy. When the direction of energy is not consistence, it creates certain kind of disturbance which affects the overall energy.
Thus, we take extra effort to string our bracelets according the most harmonious sequence, so as to bring out their highest potentials. And they are happy!