These six negative emotions are good for happiness

No one questions the value of feeling good. In fact, it seems that for the past 20 years, everyone has been on a relentless quest for a blue-sky state of mind, in pursuit of permanent residence on the spectrum between contentment and ecstasy.
Feeling bad is another matter entirely. Emotions that generate unpleasant feelings have been called sins (wrath, envy), shunned in polite interaction (jealousy, frustration), or identified as unhealthy (sadness, shame). We suppress them, medicate them, and berate ourselves for feeling them.
Because such feelings are aversive, they are often called "negative" emotions, although "negative" is a misnomer. Emotions are not inherently positive or negative. They are distinguished by much more than whether they feel good or bad. Beneath the surface, every emotion orchestrates a complex suite of changes in motivation, physiology, attention, perception, beliefs, and behaviors: sweating, laughing, desiring revenge, becoming optimistic, summoning specific memories. Each component of every emotion has a critical job to do-whether it's preparing us to move toward what we want (anger), urging us to improve our standing (envy), or allowing us to undo a social gaffe (embarrassment).
We have the wrong idea about emotions. They're very rational; they're means to help us achieve goals important to us, tools carved by eons of human experience that work beyond conscious awareness to direct us where we need to go. They identify trouble or opportunity and suggest methods of repair or gain. They are instruments of survival; in fact, we would have vanished long ago without them.
Negative emotions are not only crucial to our existence but also-ironically-to feeling good. To live optimally in the world and endure its challenges, it's necessary to engage the full range of psychological states we've inherited as humans.
Anger
An ex-girlfriend once told me she didn't know how much I cared about her until I yelled at her. That succinctly summarises a decade or two of research on what may be our most misunderstood emotion. Anger results when we feel undervalued. It prompts us to reassert the importance of our welfare by threatening to harm others or withhold benefits if others don't recalibrate our worth. This explanation clarifies why you might get angry when people needlessly try to be helpful; they haven't shown malicious intent, but they've underestimated you.
In his research, psychologist Aaron Sell has shown that strong men and pretty women-those who, over the course of evolution, have had the most power to cause harm or withhold benefits-are angered more easily than their peers. "The primary benefit of anger for an individual," Sell says, "is preventing oneself from being exploited."
If you know what you deserve, and someone else sees things differently, anger arises. Your heart rate increases, you start to sweat, you think about all the things you could do to set the other party straight. Safety, civility, practicality-such concerns evaporate. When really enraged, you can't contain your physical energy. Across cultures, people use metaphors for anger related to hot fluids in containers: You're a tea kettle or a volcano, ready to erupt.
Shame, Guilt, Embarrassment
Several years ago, Ilona de Hooge had a job as an assistant professor of psychology. "I really thought I was doing very well," she says, "but in the end I was failing completely, and I was sacked." For a month, she berated herself. "It felt as if I couldn't do anything right, that I was completely worthless. Although I failed at just one aspect of my life, it felt like, 'OK, now I'm failing at everything.'" But after a few weeks, the experience "motivated me to start looking for a different type of job where I could succeed." And that worked out very well. De Hooge is now a marketing professor at Erasmus University, where she studies shame, guilt, and embarrassment.
Humans would not be so successful-indeed, would not have survived-without social cohesion. Living among others requires all to adhere to agreed-upon social and moral norms: Don't fart in public. Don't sext constituents. Don't sock people in the nose. When we violate a norm, we need a way to pull ourselves back toward appropriate behavior. Enter shame, guilt, embarrassment to heap self-consciousness upon us.
First, they make us feel crummy. De Hooge says she felt thoroughly worthless after her firing, a feature of shame. Embarrassment, by contrast, doesn't taint so broadly.
Fear and Anxiety
One night around 10 o'clock, 30-year-old Samantha (not her real name) was walking home by herself when she passed a park and a man on a bench called out to her. As she drew near, he yanked her down, put a knife to her throat, and yelled, "I'm going to cut you, bitch!" She recounted to a researcher that, instead of panicking, she calmly looked into his eyes and commented on the choir music coming from a nearby church. "If you're going to kill me," she said, "you're gonna have to go through my god's angels first." He let her go.
Samantha lives with a rare disorder that has destroyed the amygdala in her brain, eliminating her ability to feel fear. As a result, she's strolled through numerous life-threatening situations with similar aplomb, so it would appear that her fearlessness has kept her alive-until you consider that it may be what got her into those situations to begin with.
Fear is our defender, an appropriate response to signs of threat, heightening awareness and preparing the body to escape danger. Occasionally people are overcome with fear and become frantic or paralyzed, but more often fear is initially marked by widened eyes and nostrils, acutely tuned to collecting sensory information. 
Regret and Disappointment
Regret emerges when we think about what could have been, if only we'd done something differently. It relies on counterfactual thinking-pondering alternate realities. Counterfactual thinking allows us to analyze the past and the future and to understand causality: If I hadn't done A, B would have happened; If I do X, Y will happen. It boosts learning and planning.
Because making a mistake is such an excellent learning opportunity, our emotions highlight our mistakes for us, adding regret to injury. "How could I have done that?" you wonder. "I was such a schmuck! If only I'd known then what I know now." We evolved to see the errors of our ways and to make note, often in cringe-worthy detail. There's a reason we kick ourselves while we're down: Research shows that by making our errors more painful, regret renders them more memorable and more effectively induces us to change our ways. It might be the most common negative emotion, shadowing every situation from our choice of mate to our choice of checkout line.
Regret has a trusty sidekick keeping us out of trouble: anticipated regret. When it's not paralyzing us, this fear of future self-loathing makes us wear condoms, drink less, and eat better, studies show.
Confusion, Frustration, Boredom
When Sidney D'Mello, a psychologist at Notre Dame, was learning to program computers, he'd frequently compose a program, run it, and get an immediate error message. Everything looked fine, but something wasn't working. Encountering new information that doesn't fit with the old-an error message when you're not expecting one-elicits surprise, and if the mismatch persists, you become confused. The world becomes an unsettling, uncanny place, where perception and logic are no longer reliable. The universe feels broken.
But confusion can be productive; it can force you to methodically piece the universe back together. D'Mello created a mental model of his program and ran test after test to determine which output every input begat. "That entire rich process, the abstract thinking, the testing, and seeing how a complex system works," D'Mello says, "that's the essence of deep learning."
Sadness and Grief
In 1995, Jane and Flicka Rodman were hiking the Pacific Crest Trail from Canada to Mexico. Two thousand miles into their trip, the young couple took a detour alongside a road to meet up with friends. A driver went off the road, killing them both. Flicka's mom, Barbara Perry, channeled her overwhelming grief into two projects. She set up the Jane and Flicka Fund for the Pacific Crest Trail Association, and she organized an annual two-week backpacking trip, on which she and the couple's friends hiked stretches of the trail. Each night around a campfire Barbara read from Flicka's journal his account of the trail section just hiked. Tears and laughter flowed. Flicka, a medical student, loved to write about his poop.
Failure to experience grief and sadness (and anger) after such a tragedy would be unthinkable. It would also not have led Barbara to help the organization that had helped her son so much, and she would not have brought his friends together. "Particularly when there's a senseless loss," Barbara says, "there is such a need to make something positive come from it."
Sadness comes in response to a real or potential loss and signals that restoration is needed. As a result, it motivates change, and different types of sadness stimulate different types of fix.