It is the quality of how one relates to life. The emotions expressed by humans can be divided into two broad categories. We can regard them as polarized, as opposite of each other, or we could just say that there is a dividing line where one type of emotions change into the other type of emotions. We can call the two types of emotions Negative and Positive. That is not so much as value judgment as it is a description of the main action of each group.
Negative emotions express an attempt or intention to Exclude.
Strengthening one's own position at the expense of others. Keeping bad stuff away, destroying what is perceived as a threat. Negative emotions are fueled by an underlying fear of the unknown, a fear of the actions of others, and a need to control them or stop them to avoid being harmed. Positive emotions express an attempt or an intention to Include. Taking the whole into consideration.