Emotions

What purpose do emotions entail?
In today's society, they are themes, ideals, driving forces. But why do we have them? why are we forced to suffer when we don't want to?
In our evolutionary theory, we can define emotions in one way; they are immediate reactions that enable strong reaction to survival values. what does this mean? I'll illustrate it for you.
Fear; how does this benefit us? well, fear of the dark, let's say, helped our ancestors avoid danger in the dark. Think of it this way: whoever avoided the dark, where dangerous predators roam, was more likely to survive. That's the long and short of it.
Sadness; protects reproduction value. by having an aversive feeling at the loss of a girlfriend, let's say, you try to avoid loosing the "chance to reproduce and pass your genes down to the next generation."
The same can be said for the positive emotions. happiness at the presence of a friend, for example, makes socialization repeatable. socialization helps reproduction because these social networks enable the survival value needed to become a more worthy mate.
I suggest you try to reason how each emotion enables survival or replication.