In Charles Dickens’s novel “David Copperfield,” Mr. Micawber, who has just been released from debtors’ prison, offers the hero a piece of advice: “Annual income twenty pounds, annual expenditure nineteen ninety six, result happiness,” he says. “Annual income twenty pounds, annual expenditure twenty pounds ought and six, result misery. The blossom is blighted, the leaf is withered, the god of day goes down upon the dreary scene—and, in short, you are for ever floored. As I am!”

This simple bit of arithmetic is the most important advice that is applicable in any aspect of life you want to apply it to.

When income is greater than expenditure, the result is happiness and when income is lower than expenditure, then the result is misery indeed.

Likewise, when the reality is greater than expectations, the result is happiness (even if it is only a little bit greater). And when the reality is lower than expectations, the result is misery (even if it is only a little bit lower).

Managing this difference is the key to managing for happiness.

To take this one level deeper, the expectations can be in terms of what you control for (run longer than I did yesterday, write thousand words today, read a book a week) or it can be in terms of what you don't completely control for (be a New York Times bestseller, get 1000 likes on my post).

And I don't have to spell out which one has better odds for happiness trumping misery.

Managing for happiness is no rocket science. It just takes daily practice.