Excessive aggressiveness follows frustration like day follows night. Aggressiveness on its own is not entirely negative. We must be aggressive, perhaps persistent, in the pursuit of our goal. Problems must be solved aggressively. When we're emotionally involved with an important goal we want our aggressive tendencies to come into play. However, when you are blocked and frustrated in achieving your goal your aggressiveness will seek an outlet.
Misdirected aggressiveness becomes a destructive force. Those feelings of physical violence or pent up anger towards others and yourself. Instead of a targeting a worthwhile goal, failure-type personality directs his aggressiveness into physical symptoms like high blood pressure, worry, compulsive behaviour or at other people in form of rudeness, gossip or fault finding. Upon defeat, sometimes he tries even harder which becomes a head against the wall bashing session. We should not eradicate aggressiveness but understand it and provide it with proper channels of expressions. Aggressive behaviour in animals is fundamental and is necessary to express before love. Misdirected aggressiveness is an attempt to hit one target by hitting a completely unrelated one. You don't solve one problem by creating another. Remember a time when someone was rude to you, that was misdirected aggressiveness. It is wise to not engage someone else's aggressiveness and recognize that it is not personal and misdirected. Channeling Aggressiveness
If you are blocked from achieving an important goal, you need to expel your energy. Safely. Physical exercise, sports with punching or hitting, even rearranging furniture are all excellent channels. Working towards your goal is the best way to tranquilize a trouble spirit.
The best advice comes directly from Dr Maxwell Maltz
"Write a letter to the person who has frustrated or angered you. Pull out all the stops. Leave nothing to the imagination. Then burn the letter."
Source - Psycho Cybernetics by Dr Maxwell Maltz