A remark was made about Art Rabesa-san and his energy level during and after his hachidan test. Others have mentioned the build up of intensity that comes through karate practice, and some have voiced their thoughts about how/where this energy is directed.
On the one side, during training, we practice building up an intense explosion which (we hope) can be used in a life or death situation. If we train and train and train, storing up this intensity through practice of explosive moves, what happens to this energy if it is never expressed outside of the dojo? And does it need to be?
On the other side, others may use their martial arts practice as an outlet for emotional intensity. Runners I have talked to speak of running as a kind of "therapy" that helps thinking become clearer, and emotions become more settled. I've noticed the same thing through karate practice.
It seems to boil down (or up to) the concept of passion. There are many things we can become passionate about - some about their martial arts practice, some are passionate about music, sports, work, their family, etc. Anyone who sticks with martial arts study for any period of time has to have a certain level of passion for it - regardless of their motives for training; be it self-defense, fitness, mental health, self-confidence, or any of the myriad reasons why we train.
I don't have access to statistics about this - but I've heard on more than one occasion that the longer one studies a martial art, the fewer violent altercations they become involved in - sort of a paradox if the longer one studies, the more prepared they are supposed to be. It is as if the very act of preparing to fight helps condition responses that can deter an altercation. So does karate become a de facto outlet for our violent tendencies as human beings? (The only species that intentionally kills its own kind, aren't we?)
Students have remarked to me, (and I've felt the same) that there is a certain "charge" after a workout. Aside from a good feeling from physical exercise, there is a residual energy that takes time to dissipate, which makes late evening workouts rough on those who have to retire early so they can get enough sleep for the coming workday.
This must affect different people different ways... from a feminine aspect, some of the women uechi-ka in my dojo remark that they quite enjoy the residual "energies" that their men have after a workout

To carry this dangerous subject a step farther, karate practice as a passion seems to be a very positive outlet for those pent up "tensions" - especially those of teenagers.
As an assistant to abstinence, perhaps we can add "karate" to the "safer-sex" curriculum!
So what are your feelings on karate and passion? Is it an outlet for you to deal with your deepest passions? Or does karate practice cause an intensity that you have to handle in another fashion? If so, how do you do that?
Peace and passion,
Lori