Chuck Swindoll http://www.insight.org/resources/topics/humor/ asks,
How is your sense of humor? Are the times in which we live beginning to be reflected in your attitude, your face, your outlook? Solomon . . . says three things will occur when we have lost our sense of humor: a broken spirit, a lack of inner healing, and dried-up bones [Proverbs 15:13, 15; 17:22]. What a barren portrait! . . . Humor is not a sin. It is a God-given escape hatch . . . a safety valve. Being able to see the lighter side of life is a rare, vital virtue.
A refreshing sense of humor is never distasteful, ill-timed, or tactless. Instead, it lightens our spirits and energizes our thoughts. It helps us step back and not take this fleeting life quite so seriously.
“Three tests of good humor: Can you laugh at your own mistakes? Can you restrain when it isn’t fitting? Can you enjoy it all alone?”