This is my way of looking at it. No expert though. Emotions and the way we express them are a type of communication we as a species rely on. The better we are at deciphering emotional displays, ours and others, the better communicators we become.

"Negative" emotions are normal to many species. In an attempt to control us, religion and government tell us "not to feel that way." We have bought into the nonsense that normal human reactions and emotions are a negative, that they are bad. It is not the way you feel that is the problem, it is your reaction to those feelings. Atheists, including myself, are often accused of being haters and/or of being angry. DUH! Abuses of people, non-humans and the planet make me angry and I hate the causes of those abuses. How do I deal with that anger, and yes my hatred for religion? Instead of banging my head against the wall and rolling up in a ball because I make those emotions overwhelming, I concentrate my efforts into helping others, working for causes, and educating others. Yes, the problems in the world are stronger and much more than I can handle as one person. But that is the point of being an atheist. I may not like the reality of life, but I accept it and make changes where I can. There are situations in life that leave devastating effects on people, such as surviving the Holocaust or the election of Orange Nazi Trump. All we can do is to recognize the negative, and do our best to celebrate the joys in life.

Disney made a documentary about this. They do help. Even though they're based on evolutionary paradigms far beyond our mammal ancestors, they can still be useful even in modern contexts.

Sadness can be revealing
Fear can be fuel
Jealousy can be appealing
And Anger a tool.

Fear is the basis of emotions such as anger, jealousy, boredom, and irritation. When I have these emotions I asked myself of what am I afraid.

They can help, as part of our experience in life, but not when they start to take control of the drivers seat. I'm not sure jealousy can have any positive effect, though.