What do you do when you are so ANGRY that you are seething and need to calm down in order to function?

I don't let myself get that angry any more. The last time I did, I had a heart attack. Prior to that, I'd get raging mad.

I don't let myself get the far along. If I feel something is going to escalate to that I shut down before then. My husband taught me before we were married that if you get quiet, people will stop. They will then start to wonder if they won or if they should be afraid.

(FYI it wasn't me he was mad at when he taught me to be quiet.) 

There are only 2 people that would get me that mad and I haven't been around them in 15 years. Otherwise, I'd take myself away from them and everyone else. I have to be alone in situations like that.

I came to a place in life that that extreme doesn't come into play anymore. Becoming unhinged allows the situation to beat you, helps the bad guy win. I refuse to hasten my own defeat by losing my cool. Step back and take account. Simple as that.

Punch someone across the face. Works for me.

Usually when I get that angry, it's over something I have no control over. That gets me frustrated the most. I will take a few minutes and go over the situation in my head. I pinpoint what's gotten me so mad. I try to think of another way around whatever it is.

If the situation involves someone else, I try to find out if there is any way to change the outcome. If not, what's the worst thing that can happen? If there is nothing I can do, I ask myself if I'm more angry that I can't control this situation or do I actually have a legitimate complaint.

Sometimes, you just have to breathe your way through it. Change what you can. Walk away when you can't.

I don't get mad anymore.  Years ago, in a rage, knocked someone down and was trying to drag them face first thru a bunch of broken glass.  A couple of bystanders grappled with me long enough for my intended victim to make a getaway. 

After I calmed down, I realized just how serious the consequences of my action could have been.  I realized that me becoming enraged was not a good idea and made a conscious effort to change.  And did.  . 

I used to get angry when I was much younger. These days I don't think I take things seriously enough for high-level anger.

Walk away. Go for a walk, clean, do some gardening.

In fact my instinct is to get distance mentally or physically, however when it's your neighbour that is causing the problem and is beyond reason, and you've exhausted all avenues, it isn't easy because "Home" becomes the place you dread.