Understand the nature of emotions

Think about the negative emotion that you felt recently.
Recognize that this emotion was not so terrible. Take note of how it comes and don’t identify with it. Note how that emotion is absent from your current reality.

Recognize the purpose of that negative emotion.
Consider what you can get from that emotion. What did you learn from that emotion, and how did that emotion affect your personal growth and development?

Consider how that unpleasant emotion stained all of your experiences.
Did you find it necessary to identify with this unpleasant emotion, or were you able to separate yourself from it? Has this one bad feeling attracted plenty of other negative emotions?

Recognize how that one emotion affected your mental state.
Take note of how you turned that emotion into mental agony by adding your judgment to it.

Adopt the attitude that you are responsible for what you feel.
Acknowledge that your destructive emotion exists only in your head and depends only on how you interpret reality.