The recent news about Robin Williams reminded me of the following quote from the Gilbert and Sullivan opera The Yeoman of the Guard:
Cause? Have we not all cause? Is not the world a big butt of humour, into which all who will may drive a gimlet? See, I am a salaried wit; and is there aught in nature more ridiculous? A poor, dull, heart-broken man, who must needs be merry, or he will be whipped; who must rejoice, lest he starve; who must jest you, jibe you, quip you, crank you, wrack you, riddle you, from hour to hour, from day to day, from year to year, lest he dwindle, perish, starve, pine, and die! Why, when there's naught else to laugh at, I laugh at myself till I ache for it!