Characteristics of Emotion

It is experienced in response to a particular internal or external event which leads to physical arousal in the body. For example, when you discovered adulterous act of your girlfriend, you blood pressure may increase in a reaction to this event.
It motivates to take certain actions such as seeking things and activities that provide pleasure and avoiding those that give rise to pain or unpleasantness. For example, compassionate emotion motivates us to help others (inner-satisfaction) and avoid causing harms to others.
It arise out of our sensations, perceptions and thoughts related to objects, persons and situations.
It varies in their intensity. For example, happiness can be experienced as pleasant and contented at the lower end of the continuum whereas excited and thrilled at the higher end of the continuum.
It can be desirable or undesirable to an individual, depending on whether the said event is perceived as ‘positive’ or ‘negative’ one.