Emotions are important because they quickly provide us with information about the world around us, so that we can behave in an adaptive way. In other words, emotions drive us to behave or do things.
Although some emotions may be more pleasant to experience than others, such as joy and happiness versus sadness or anxiety, there really aren’t any “good” or “bad emotions”, because we need them all to give us information.
For example, imagine you couldn’t feel fear. Then imagine walking down a street at night and starting to turn down a dark alley-way with what appears to be a couple of shady looking individuals in the middle of the alley. If you didn’t experience any fear, you might continue down the alley-way and potentially get mugged. Your internal alarm system thus gives you information about your environment to guide what you do.