They say it is healthier to let out emotions on paper rather than burst out into the world. A cathartic dream is a dream during which you let out all the emotions hidden deep inside from all your life. You feel free and relieve while you are awake. These dreams tend to happen in times of emotional distress, loss, or grief. There have also been reported dreams with a violent theme where you get to release pent-up emotions or actions of revenge against someone who has wronged you.
Breaking glass, fire, furniture and what not. Most people associate these actions as the release of pent-up anger or frustration if dreamer can not take any excessive actions in real life. It is a common scene for cathartic dreams wherein the individual cannot calm themselves down and needs to inflict pain on objects to release their pent up emotions.
As we dream, our brains discharge our emotional experiences. We are dreaming to release pent up emotions. Often our emotions when we are awake and seen in the context of the waking state, may seem excessive for what triggered them. It is as if these happy or sad emotions that woke us up were so strong that they could not be contained or bounced back under control by reason during the hours of sleep. This is in line with cathartic dream formations showing that in dreams there is an irrational release of pent-up emotional damage due to their repressive effects on day-time feelings during waking hours.