Patience is important because it forces us to pay attention to details which we might overlook in our rush to achieve. Patience also allows us to bring our energies and focus to a fine point, so that nothing is wasted as we set about accomplishing that which is ready to come to fruition.
To borrow from the equestrian arts, patience is the half-halt which brings us back into balance. It catches our attention. Patience allows us to overcome the inertia of entropy; it is the means by which we recollect ourselves. Patience allows us to keep a soft hand on the passions which might otherwise lead us to fall apart as we rush around at the speed of the world in pursuit of fulfillment.