Emotion is "energy in motion." We live in a world full of emotions. Emotions are the most powerful factor in one's life, because we relate to others according to those emotions.
The main conflict in human life is due to disharmony in the realm of emotion. This disharmony sometimes manifests in the form of: anger, hatred, jealousy, frustration, love, affection, happiness and sorrow.
Yoga helps with channeling the intellect, feelings and emotions in the right direction. Learning to live with presence and intensity, whenever we hold an angry or anxious thought it denies us a happy thought. We should be rejoicing and celebrating in our achievements and those of others.