“Joy is not produced because others praise you'

What is your understanding of the last paragraph (below) of The Road To Character? (p. 270)?

“Joy is not produced because others praise you. …Joy comes as a gift when you least expect it. At those fleeting moments you know why you were put here and what truth you serve. You may not feel giddy at those moments, you may not hear the orchestra’s delirious swell or see flashes of crimson and gold, but you will feel a satisfaction, a silence, a peace- a hush. Those moments are the blessings and the signs of a beautiful life. “

How does this statement apply to the work that human service workers perform?