From Billtry by Mary Kyle Dallas, 1895.

"Your right to be unhappy."  From The Australian Women's Weekly, 1961.

From Elson-Gray Basic Readers, Book One, 1937.

"World's unhappiest man."  From the Bombay Sunday Chronicle, 1939.

"If only there were some slight chance for just one moment of happiness in our lives!"  From Dark Shadows episode 1205.

Unhappy mermaid.  From Spellbound, 1977.  (Courtesy of Archive.org.)

"Where does discontent come from?" (Nation's Business, 1946)

The longest answer we found said: "Discontent comes from desire for reward for the works done, from selfish ambition, from covetousness, from love of men's praise, from dependence upon earthly prosperity, from absence of religious ideals, from failure of the good of charity in the heart" (New-Church Messenger, 1909)

The shorest answer we found said: "Discontent comes from the imagination" (Thought, from the Learned Societies of Canada, 1961)