First off, I don't think you have anger issues as bad as you might think. The angriest people aren't aware of their anger. If you are aware that you have a level of anger that is affecting your ability to enjoy day to day life, then you aren't in the worst of spots.
As LINUX already said, a human has thousands of thoughts a day. You will have fleeting thoughts of anger, lust, jealousy, annoyance and the whole gamut in a given day. There isn't going to come a day when you no longer have anger, anxiety or any of the like -- the hope of maturity is developing the skillsets to handle these conflicting emotions.
Generally speaking, anger usually bridges over unmet needs. Anger is usually a sign that something is wrong in your life. You might not be paying attention to your own needs enough, you are avoiding dealing with depression or -- if you are very young -- simply maturing and are justifiably impatient with the haphazard and confusing process of growing up.
Regardless, as you already seem to be aware, anger is both destructive and addictive. It is destructive because it consumes your thoughts and prevents your ability to be rational and enjoy positive emotions. It becomes addictive as it crowds out your ability to enjoy life as you wait for the times you feel you can lash out. The more you give into the anger, the more you feel you can indulge the anger and use it to feel better about yourself.
Venting anger doesn't work. Sure, sometimes hitting the gym can help you cool off, but it doesn't take care of the underlying issues that caused your anger in the first instance. Venting the anger usually means indulging the anger, giving it a footing on which to stand. It seeks not to heal, but to perpetuate itself.
If you want an extreme example of what happens when anger goes unchecked, check out Tumblr. The SJW's & feminists are walking containers of unregulated anger and self-righteousness. Hungrily seeking out their next fix (outrage-inducing event) like an addict might, they only really exist during their explosions of anger. Having neglected any true sense of duty to the self or learning to turn that destructive anger into more constructive channels, they have allowed themselves to be completely controlled by their anger.
Now, since anger usually lies over top of unmet needs, what you need to think about is why exactly you think you have issues with anger. Very rarely in a person's life is one singular issue contributing to feelings of anger -- usually it is a small number of unmet or under-met needs that is causing you irritation.
As we have preached on this forum, an often unmet need in a man's life is his health. We are talking nuts and bolts here: getting enough sleep and enough water and nutrients. The benefit of working out might not be that it is helping you vent so much as it is helping you get the exercise your body needs. It should also go without saying that a regular sex life ratchets down anger as well.
As CrashBangWallop has suggested, you might be in need of some real "me time." Spend some time meditating, reading or engaging in activities that can help you can some insight into the workings of your own mind. This isn't getting high or goofing off playing video games, but some dedicated time spent trying to understand yourself.
If this last part sounds like mental masturbation, it just might be. These sorts of issues don't lend themselves at all to cut and dry solutions. Here is an old post by myself on this forum:
"Walking Distance," On Why The Past Is Best Left In The Past. Writing is cathartic for me, as is writing with a specific life lesson in mind.
If you are looking for something more concrete, here is a link to an excerpt from a book called "Seeking Safety:"
Healing From Anger. Ignore the part at the end about the anger contract -- just read about anger and how to deal with issues around anger.
