I'm not saying that we should slam ourselves into walls when we are angry or upset, but just to recognize that our primitive brain is wired such that when the flight or fight response gets triggered it is good to let the system flow and flush. Otherwise the biochemical soup that is designed to speed and strengthen us floods our system and does not get used, often resulting in unwanted side effects. The extreme of this is post traumatic stress syndrome, and I suspect that given the constraints of our sedentary and technological orientations that many of us are walking around with adrenaline based emotions stored in the cellular structure of our bodies. Symptoms include and are not limited to sleep dysfunction, physical illness, chronic pain, an exaggerated startle reflex, nightmares, difficulty relaxing, anxiety, and depression.
It has been observed that animals in the wild are rarely traumatized, whereas domestic animals and humans frequently are. Wild animals usually give an energetic reaction to their stress events that releases the adrenaline and other chemicals that were generated in support of intense movement. In situations where the "freeze" response is used instead of fleeing or fighting, the animal vigorously shakes itself out of that state when the danger is past. One reason domestic animals may have more trauma stored in their bodies is that they are often restrained and not allowed to run out their experiences. I knew a horse named Arrow who could not tolerate to have his head tied because in his past he had been severely beaten while tied to a post so he could not get away. He was the sweetest, smartest horse you could ever hope to ride; but when his head was tied he went berserk and would hurt himself and anyone near him. Domestic animals may evidence more trauma in that they have acclimated to spending time with people, and we have our issues about emotions. Many of us humans have been taught to keep our feelings in, to deny them or intellectualize them, and have had no release for the accompanying biological stimulants that end up stored with the memories in our cells. In our culture people are often told "don't cry", "be a man", "you shouldn't feel that way", and if we exhibit strong feelings or find ourselves shaking after an experience are told "here, drink this, take this pill", and numerous other injunctions designed to suppress our emotions. Or some of us lose control of our feelings, and like Arrow, hurt ourselves and others; so maybe we clamp the lid down harder on our feelings..... until the next time they erupt and the cycle starts again.
Suppressed emotions coagulate energy. To keep from accumulating energy blockages, find safe outlets for emotional experiences as they occur instead of repressing the feelings. Talking to someone you trust, running or other physical exercise, visualization, chakra balancing, journaling, dancing, singing, drumming, and other expressive modalities are helpful in giving release. And if you suspect you might be harboring some old emotions that block the full flow of your life force, hypnosis and the energy psychologies (TAT, EFT) have proven very effective in clearing emotional blockages. All of our emotions are gifts and have significance; one of our lessons here on earth is to learn how to work with them for our highest good and benefit.