I think anger itself can be a powerful and important emotion. PArticularly for someone not comfortable setting boundaries, it can allow that person to make boundaries. It can also level the playing field in a disempowered situation. Particularly if anger can be expressed without blame, it can be very powerful and important. My DH has a tendency to allow himself to be walked all over; he was by his ex, anyway, and carried those habits into our relationship. Anger allowed him to leave her. In our relationship, sometimes I am just fed up with the circumstances, and I am complaining to him. I usually takes him getting angry to really set a boundary; sometimes he yells, but always says true things: "It hurts my feelings when you say those things! I just need a break! I do not want to hear about how my life is to much for you! I love you!" Sometimes I need to hear that in order to be there for my mate. It might be nice if he could say this when he is calm, but he has habits of disempowering himself, of feeling like his boundaries are not important, only mine are. So it takes anger to break through his accommodating habits. Without this, I would not know how much I am hurting him...he would probably just get tired of my frustration one day without me knowing.
I think when we are in disempowered situations, anger can make us give voice to our piece. This can be so with an unfair boss, with a bureaucracy, and so forth. It may feel nicer just to smile and nod, but it does not necessarily allow us to be our whole selves. I think self expression can happen without anger, but often our inhibitions make us comply when someone else has the power. Without anger, the boss may never hear how hard she is on her workers. She may NEED to know this. I think there is huge value in learning how to express anger in a non-destructive way, in a way that is respectful of the others' point of view without giving up any of your own ground. Conflict can be a great way for people to get better at making the needs of all be met, particularly if conflict can be peaceful. I remember how liberating it was for me to tell my mom, "When you say I am ruining your life, I feel really hurt and angry at you." I remember clearly that I did not blame, but was able to express intense anger in a totally peaceful way. This was hugely helpful for me in being able to love my mom more, because the stale resentment I had was blocking love.
Anger is also an emotion that has negative physical impacts on our bodies. But so does stress, which results from stuffing anger.
We are talking about venting, and about how it might perpetuate anger and aggression. To the degree that anger can be what it takes to empower us to take care of ourselves when we are in "one down" situations, venting is a tool for keeping anger strong even when the ill is not happening. For any of those who have studied abuse and the "cycle of violence" concepts, a real problem for people in abusive relationships is that they get stuck in a cycle where they are either dealing with crisis, and thus do not leave the abuse, or in a peaceful cycle, and not wanting to leave. I think this is true about any time we are being oppressed--when someone has power over us and it is working for us (we are getting what we want), we do not want to rock the boat. When it is not working, we are too afraid to rock the boat. It is okay with me for people to have power over me much of the time, but sometimes it is not.
With the BPD person in my life, she wields giant power, because she is willing to be crazy and violent. PArticularly when she does this in front of the kids, I have little power to do or say anything. I am also structurally disempowered as a step-mom, so I have no rights to make her stop (unless she is doing stuff that is prohibited by criminal law). Most of the time, I am kind and walk away. But when things get to intense, sometimes I have been able to get her to stop. With her, my anger is totally managed--i do not yell or be mean. But it helps me to be willing to set clear boundaries that are not negotiable.
Here is the problem. With a BPD person, the truth is that because that person is mentally ill and cannot change easily, my power (using whatever tools I have) is limited. The reality is that what I want from her is not possible. The only way I can REALLY level the playing field is to be happy, and to create social boundaries around her to limit her power (boundaries that might include court orders, and also having her friends and the kids teachers know who she is and what is going on, so her stories do not get traction). But trying to make her care about my feelings, or not hurt her kids emotionally--she cannot do that, and I cannot make her. It is like yelling at a flat tire to get it to be not flat.
Anger can be helpful where someone has the capacity to change. I am not saying it is the best method, but for some people in some situations, it takes anger to be willing to risk.
What I have found is that for DH and I, anger has lead us to create boundaries at times, and is good in that way. But the same stuff happens all the time, so if we are always angry, we have to deal with the physiological effects of these feelings on ourselves and our happiness. Complaining does sometimes propel us into action, but there is too much that is upsetting to really act on it regularly. It is true that I think my DH learned to vent once he left his wife, and sustaining that anger, rather than living in fear, made him make choices that are better for the kids and him. He is not a raging or difficult person when angry; he does not get stuck there. But he just REALLY avoids conflict unless he is angry.
For me, I set boundaries without anger. With the kids, some of their more enmeshed lying and intense behavior results in anger in me...and while I do not always feel great about how I express it, I always do it with love and limited blame, and I think it helps SD11 see when she is being hurtful. When she is mimicking her mom's worst, I am not sure it is bad for her to have someone respond with appropriate anger. "I do not like being treated that way. I feel angry at you right now." I think me just avoiding dealing with her when she acts that way is easier for me, but is alienating. Closeness involves knowing when you hurt someone.
In sum, venting is does perpetuate anger. When we are powerless, sometimes we need anger to motivate us and lessen inhibition around rocking the boat to get what we need. Because there is danger when the anger arises, we use venting to keep our feelings strong into peace time, when action may be more useful. But with a BPD person, if we responded appropriately with anger to each outrageous event, we would be angry all the time. If my DH did once what BPD mom does all the time, I would probably have left him a long time ago. But with BPD mom, there is not a lot I can do. Feeling angry does not feel good to my body, so I have to try to inhibit my natural response to her. Again, my anger is pretty mellow. I have never been violent with anyone in my anger, and I usually am not even very blaming.
So venting makes my life unhappy. It is not that I want not to be angry with her because it does not help; it is because I feel bad when I feel that way a lot. Anger IS useful, natural, important, but not necessarily the most effective tool if we can manage and deal with our feelings. But when someone is not able to change or be influenced by our feelings, that lack of inhibition anger creates does not help. So to keep up with the anger feels bad to us, with no change to them. So we have to override the circuit somehow to feel good.
As a contrast, let me relay an example from my young life. I was an employee of a grumpy, controlling person. I took care of her disabled child. She was gruff and rude every morning. After a year of working for her, one day she was really mean. I finally got angry, and told her that I felt angry, and that it really hurt my feelings when she was mean. She was shocked. She had no idea that I felt that way, and she told me that a lot of people in her life feel that way. She told me her husband feels that way, her non-disabled son, and lots of co-workers. But no-one bothered to tell her how it made them feel. She cried, I cried, we became great friends. This is a person who has habits of being rude and controlling, but who is not mentally ill and DOES have the capacity to change her behavior in response to new information . My anger gave me the push I needed to share my feelings with her, and we were both the better for it. I am sure I vented many times over the course of being her employee.
I think the idea that venting (as the term implies) "let's off steam" so we do not blow up CAN be true, when the situation is so extreme that venting is a lesser state of intensity, and when the consequences of speaking our anger to the person it involves are too great. But in general, venting perpetuates anger. There are times this is useful, and times when it is not. But whether or not it is useful, it can be destructive to our well being over time; also, our anger tends to make it harder to get allies.