We are not meant always to be happy, and who would want to be? Happiness would become meaningless if it were a constant state. If you accept that, then you will not be surprised when something bad occurs, you will not gnash your teeth and ask, "Why me? Why has this happened to me?" It has happened to you because that is the nature of things. No one escapes. The rainbow comes and goes. Enjoy it while it lasts. Don't be surprised by its departure, and rejoice when it returns.
-- Gloria Vanderbilt, The Rainbow Comes and Goes, p. 274