Sadness, as a basic human emotion, is unavoidable in life. People you love will hurt you, and get sick and die. You'll fail at things. Bad events will happen, and you can't stop them. Fortunately, sadness is a temporary state (unlike depression, a long-term mental illness), and according to experts, it's an emotion that can actually be good for you.

Being sad can make you more creative.

It depends on how you handle your sadness, however. Researchers studied 244 college students and tracked whether they engaged in brooding (repeating negative thinking over and over) or self-reflective pondering (examining one's thoughts and figuring out what to do about them). They found that pondering was associated with higher levels of creativity, whereas brooding tended to only make participants feel worse.

Sadness elevates motivation.

When you're happy, you really don't want anything to change. But being in a negative emotional state is uncomfortable, a prompt that moves people toward action. Joseph P. Forgas, PhD, professor of psychology at the University of New South Wales in Sydney, Australia, conducted research in which participants where shown either happy or sad movies and then tasked with answering multiple difficult questions. The happy participants did far worse than the sad ones, spending less time, answering fewer questions, and getting less of them correct.

Your lows help you appreciate the highs.

Helen Russell, author of The Atlas of Happiness, explains that the Brazilians use the word "saudade" to describe the absence of and longing for happiness which once was. And researchers have discovered that making room for transient sadness helps people notice details, persevere, be more generous, and count their blessings. "Saudade teaches us that a degree of melancholy in life is inevitable -- desirable, even -- and something to be savored rather than ignored," she writes. "No one can be carnival-happy all the time, and the lows help us appreciate the highs."

Your happiness will probably return.

According to Art Markman, PhD, professor of psychology and marketing at the University of Texas at Austin, humans have a set point for happiness. So, at some point, weeks or months after your difficulty has passed, you'll probably feel as happy as you were before the negative life event happened. "That doesn't mean that events can't have a long-term influence on how happy you are," he writes, "just that the best predictor of how happy you will be several months after a big positive or negative event is how happy you were before it."