Happiness is the feeling that power increases—that resistance is being overcome.

—Nietzsche

This famous definition sticks in the throat a bit because of Nietzsche's dark reputation and how it makes that “power” sound, but try a small substitution with modern therapeutic language: “Happiness is the feeling that you are being empowered” and notice how differently it hits. Or how about this very slight modification: “Happiness is the feeling that you are moving in the right direction”?

Looked at this way, Nietzsche turns into an old softy, offering us a surprisingly gentle and generous definition, in which happiness is no destination, no distant mountain peak where all is well forevermore, but something accessible, even easily so. No matter what gloomy valley you find yourself in, one step up into light—and even into power, if you will—is enough.