Happiness is overrated.
According to Susan David, Harvard psychologist and author of "Emotional Agility," so-called "bad" emotions are actually good for you.
"Life and our contract with life means disappointments, frustrations and failures. Unless we are able to learn from our emotions we will never be able to move forward effectively," she says in the video above.
David lists anger, sadness and fear as emotions that typically have negative connotations, but she argues that they all have positive traits, and can be highly useful and even world-changing.
"Anger is often seen as a bad emotion but no one ever changed anything in the world without experiencing some level of anger at the status quo," she says. "It tells you things that are important to you, that you are bumping up against, in terms of your success."
To find out what she has to say about fear and sadness, and how they can be helpful to you, watch the video above.