Much in life cannot be affected†but must be borne†without complaint, because complaints are a bore†and undermine the serenity essential to endurance.

-Acheson, Dean Gooderham
Quoted in Gaddis Smith  American Secretaries of State (1972).

Mirth is short and transient, cheerfulness fixed and permanent† Mirth is like a flash of lightning that breaks through a gloom of clouds, and glitters for a moment: cheerfulness keeps up a kind of day-light in the mind, and fills it with a steady and perpetual serenity.

-Addison,Joseph
  In The Spectator, no.381,17 May.