When a competitive colleague relishes in the failure of another, or a University of Kentucky fan cheers against Duke University's basketball team, both are experiencing the same emotion, but might not be willing to admit it.
In German it's called schadenfreude, stemming from two words meaning harm and joy, and everyone feels it at some point, said Richard Smith, author of a new book The Joy of Pain: Schadenfreude and the Dark Side of Human Nature.
In his book, the University of Kentucky psychology professor combines personal experiences with examples from popular culture and history to describe the emotion, its causes and how to control it.
"We are self-interested beings," Smith said. "Schadenfreude speaks to the competitive side of us that is out for ourselves."
Though schadenfreude is often hidden, it's prevalent in rivalries of love, politics and sports because people gain from another's misfortune. And it happens much more often than people are aware, he said.
"It's more part of the fabric of everyday life than I thought before," Smith said.
A frequent cause of schadenfreude is envy, he said. When a person envies someone who is similar, but who is perceived as more successful, the envious person is likely to feel schadenfreude if the successful person fails or does something wrong.
"Much of life involves competition," he writes. "One side must lose for the other to win."
One example Smith gives in the book is the basketball rivalry between UK and Duke.
Smith has conducted research on the topic, examining the emotions felt by dedicated UK basketball fans when something bad happens to the Duke basketball team, such as the loss of a game.
The dedicated fan often feels strong schadenfreude, although it's accompanied by strong sympathy, he said.
"Any type of misfortune befalling rival teams, such as injury or scandal, is red meat for people highly invested in their own team," Smith writes in a chapter titled "Others Must Fail."
A more serious example Smith provides is the Holocaust.
Stephen Thielke, a psychiatrist and professor at the University of Washington, said Smith carefully shows how envy and schadenfreude were important factors for the Nazis. Thielke explained that some of the core emotions that caused the Holocaust can be seen in everybody.
"It's important to acknowledge that everyone has a dark side," he said.
Thielke, who has collaborated with Smith for a number of years, said schadenfreude is a complicated emotion to understand because it's hidden — people don't want to admit it.
"Schadenfreude is everywhere — even if we don't talk about it much, even if we don't admit it to ourselves," Thielke said.
The book is a great opportunity to reflect on one's emotions, he said.
"I see a much bigger purpose of the book," Thielke said. "It can help us all to live better as individuals in society."