Perhaps that question, What makes you happy?, is central to most literature. If you want a warm story, you write about what makes the character happy. Sure. If you want a dark story, you write about what makes someone unhappy...or about a character who is only happy if he/she is making someone else unhappy. If you want a thriller, you write about what could potentially make someone (or their relatives), permanently unhappy. If you want to write about extreme swings of happiness and unhappiness, you write a romance or war novel (same thing).

And there is a point. Here is an article from the Atlantic about some amazing Harvard University research whereby they followed the lives of 268 men who entered college in the 1930s "through war, career, marriage and divorce, parenthood and grandparenthood, and old age." They refer to this as longitudinal research. (In case you're wondering, women attended Harvard's sister institution of Radcliffe College exclusively until after WWII.)

One multi-paragraph teaser snippet of one of the 268 cases:

After college, you got an advanced degree and began to climb the rungs in your profession. You married a terrific girl, and you two played piano together for fun. You eventually had five kids. Asked about your work in education, you said, “What I am doing is not work; it is fun. I know what real work is like.”....Two years later, at 49, you were running a major institution. The strain showed immediately. Asked for a brief job description, you wrote: “RESPONSIBLE (BLAMED) FOR EVERYTHING.” You added, “No matter what I do … I am wrong … We are just ducks in a shooting gallery. Any duck will do.”....Your first wife had died, and you treated your second wife “like a familiar old shoe,” he said....But you called yourself happy. When you were 74, the questionnaire asked: “Have you ever felt so down in the dumps that nothing could cheer you up?”..."You circled “None of the time.”

Another, Case No. 47: You literally fell down drunk and died. Not quite what the study had in mind.

To see the rest of the article, go here.