It served writers well in the age of chivalry, when they strove to remind their rich and powerful readers (the only kind; everyone else was illiterate) that the best things in life came not from titles and trappings, but hard work and a positive attitude.
Geoffroi de Charny asked every reader to "be a man of worth;" Geoffery Chaucer, to "make a virtue of necessity."
When you worked hard and maintained an "attitude of gratitude," sudden setbacks (the "necessity" in Chaucer's phrase) wouldn't throw you.
Alas, chivalry's dead; not so, reversals of fate.
Riding the Wheel of Fortune is still dangerous.