Anger is an ironic emotion. It starts with irritation at a lack of control, then gradually becomes a more and more controlling force of its own. Whatever initially provoked the anger is then eclipsed by anger itself, to the point that one has no choice but to surrender to it.
Like any source of energy, anger can be harnessed and directed toward productive tasks: work, play, and creativity. A good way to deal with a small amount of anger is to defuse it by burning it off like extra calories. This gives an irritated person control over anger, instead of vice-versa.
Rage is something else entirely, and cannot be directed into productive or rewarding tasks. We've all experienced degrees of rage at some point, and most people know that the easiest way to deal with rage is with escapism, preferably a form of entertainment that does not kill many brain cells. Rage is the result of long-standing anger that has been given too much free reign, allowed too much control, and dealing with rage will eventually involve an acknowledgment that one gets something out of it, a rush of neurotransmitters, a uniquely thrilling experience that can easily become an addiction.
Such an acknowledgment might seem counterintuitive because intense anger can be very unpleasant. An enraged person will lack the presence of mind to be able to examine their own experience of this condition and arrive at the conclusion that rage has become their drug of choice. They will only understand that they have given up control in some sense, escaped into an alternate state of mind, and that this alternate state of mind isn't especially healthy. And just like any other kind of addict, it will take a certain amount of sobriety for an enraged person to regain some perspective.
Successful anger management might involve talk therapy, medication, or a combination of the two, but like any other method of self-improvement, it will ultimately depend on the ability of the angry person to maintain sobriety and perspective. Given the choice of experiencing the thrill of rage or choosing a different path, the rage addict must consistently choose a different path. This often requires enormous self-discipline of a variety that most people lack, which is where the support of friends and family can be essential.
It's helpful to identify the origin of anger and address it immediately. A constant source of irritation can become a crutch for someone predisposed to anger, so even small irritations should be addressed productively as soon as they crop up. For many people, it's possible to simply roll with the punches, exercising patience and keeping a sense of humor in traffic jams and long supermarket lines. For a person whose anger has transformed into rage, such situations can become crutches, rationales for surrendering to anger. This is no different from an alcoholic who makes exceptions for drinking on holidays, and remaining mindful of even small amounts of anger is necessary for the anger addict's recovery.
Negativity is not always unhealthy, and anger is an unfairly maligned state of being. Nothing is healthier than responding to irritations with small amounts of anger. It's an emotion that motivates people to define their values and priorities, recognize problems, and work at solutions. But when this process operates a low level, continuously and beneath one's radar over the course of years, it becomes a self-reinforcing tendency that is no longer connected to its purpose. Interrupting this self-reinforcement and breaking the "snake eating its own tail" dynamic of anger can be very difficult, but is ultimately necessary for restoring one's psychological health.