With the focus on Positive Psychology, it can sometimes seem like the goal is to always be "happy". Positive Psychology teaches us there are many benefits to using happiness as a tool to help us lead a fulfilling life. But researchers also remind us there is value in "negative experiences".
Psychologist Todd Kashdan, the author of The Upside Of Your Dark Side: Why Being Your Whole Self—Not Just “Good” Self—Drives Success and Fulfillment,
has found in his research that negative emotions encourage people to take productive action or reframe events of the better.
"Getting
into a fight with your partner may strengthen your relationship, or
feeling anxious about a test can increase studying, thus chances of a
better grade."
Kashdan isn't saying forget about happiness. He's simply
suggesting we focus on the positive 80 percent of the time — this
includes kindness, compassion, and gratitude — and the “negative” 20
percent of the time. So like, the 80/20 rule, but for mental
health.
http://www.medicaldaily.com/positive-psychology-prematurely-discards-negative-emotions-why-its-ok-be-sad-and-316636
Click here for a description of the 80/20 rule.