The existential void
Living without awareness of our true nature is empty and full of ups and downs, from small up to chaotic. It is a mechanical life, a life of incompleteness, disharmony and discontentment.
If we are not aware of our divine Being, if we ignore our true Self, our Essence, that which gives life, fullness and meaning to everything, then we cannot live with fullness and plenitude; we will always feel an existential void which we will try (in vain), to fill it with superficial sense experiences, pleasures, material success and sensory objects.
If our every action, deed, thought, emotion doesn't vibrate in harmony with our soul, we cannot live with harmony, unity and fullness, always something will be missing.