When a person hasn't in him that which is higher and stronger than all external influences, it is enough for him to catch a good cold in order to lose his equilibrium and begin to see an owl in every bird, to hear a dog's bark in every sound.
Individuals we consider happy commonly seem complete in the present and we see them constantly in their wholeness: attentive, cheerful, open rather than closed to events, integral in the moment rather than distended across time by regret or anxiety.