Many people seem to find no satisfaction in life and they walk around in discontent lacking fulfillment. Paul stands in stark contrast to these when he gives his testimony in Philippians 4:11-19.
Paul writes from terrible conditions being in prison, yet he said he was content even in this situation. He said, contentment is learned. The situations of life are a schoolhouse to learn contentment, but some never learn and thus their lives are unfulfilled, unsatisfied, and unhappy.