Ilchi Lee, in his book Power Brain Kids, writes: “We say, ‘This makes me happy’ or ‘That makes me mad,’ but in reality, emotions come from within ourselves, from inside our brain.” We need to master our emotions to take full ownership of our brain.
Children can change from one emotional state to another a lot quicker than teenagers or adults. By learning to identify these emotions, it will be easier for them to let go of emotional states as they gain the skills to cope.
As a parent, you need to let your child experience, express and talk about any emotion that he or she may be feeling or witnessing. It is your job to communicate with your children on the meaning associated with these particular feelings. Otherwise it’s easy for children to confuse their emotions. For example, explain that their faces and inside feelings are clues to their emotions.
Lee suggests the following exercise, happy face/angry face, to introduce the notion that your children can choose which emotions they feel. It will also help drain your child of past negative emotion.
From Ilchi Lee (Excerpted from Power Brain Kids):
• Remember a time when you felt very angry or unhappy. Tell about that time, and then blow up a balloon, imagining that all the anger is going into the balloon.
• Tie up your “angry” balloon and draw an unhappy face on it with a permanent felt-tip marker.
• Now remember a time when you were very happy. Blow the happiness into a second balloon.
• Tie the “happy” balloon. Using the marker, draw a happy face on the balloon.
• How does each balloon make you feel when you look at it? Pop the one you least prefer.
Popular Brain Tips 
I’m sure you’ve seen it before, a child throwing a temper tantrum in an aisle at the grocery store and then happy as can be a couple of minutes later (he’s already forgotten how important that lollipop was). Emotions and feelings can be confusing to a little one. They’re even confusing to most adults.
I prefer the happy face, don't you?