On gratitude

From everything that comes about in the universe one may easily find cause to praise providence if one possesses these two qualities, the capacity to view each particular event in relation to the whole, and a sense of gratitude.  For, otherwise, one will either fail to recognize the usefulness of what has come about, or else fail to be truly grateful if one does in fact recognize it.

Epictetus, Discourses 1.6.1-2