I recently have listened to a sibling and a friend vent about their anger at someone who "made me so mad!" We have all felt this way: Someone doesn't call, doesn't follow through on what they said they would, didn't live up to our expectations, and then we get angry and the venting starts, and pretty soon we are so worked up we literally have heartburn.
Spoiler alert: "They" don't make us mad. We make ourselves mad.
Something happens, like someone doesn't call, and we get mad. WE get mad. WE decide how to feel about the event that happened. The other person has nothing to do with our response to the fact of what happened: It's our expectations, judgments, beliefs, conditioning and habits that make us respond as we do. And, unfortunately, most of us are stuck in responding quickly and emotionally when things happen. If our parents instantly got mad at others, and started swearing and venting and calling them names or whatever, then we learned that is the way to respond, for example. If our childhood friends got mad and name-called or shunned others, we learned that as another way to respond. Family and peer-group patterns are very strong influences in the development of children and adolescents. Unfortunately, video, television, and movies show very potent and graphic displays of anger, and most are connected to power and humiliation, and so we have those behaviors modeled for us all over the place.
Changing our response to events is challenging, but our feelings are our responsibility, no one else's.
You've heard of Pavlov's Stimulus Response Theory. Well, we are not dogs (most of us), and humans have a third hidden step in that formula most of us aren't even aware of: Choice.
Stimulus > Choice > Response.
When an event happens (someone does something we don't like), we can decide to stop, give our hearts and minds a moment to decide how to think and feel before responding. This is difficult at first, and takes a lot of practice, but then becomes very easy because you feel in control, and then don't get yourself all worked up about things, wasting precious time and energy.
An example: If we expect someone to do what he says he will do, even though he rarely follows through, we have an expectation that is setting us up to be disappointed and potentially mad. If we stop to think about it, he doesn't ever follow through, so assuming he won't means we can go about whatever we need, and not be in a place of wasting energy being angry. It's a bit sad, especially if it's a child or someone we love, but keeping our expectations very low means we won't be disappointed and get upset when he doesn't call. We have to remember that person is stuck in their patterns (of not being responsible in relationships, etc.), and only they will be able to change that. Us getting mad at them won't change a thing, and will only waste our time.
It's painful to detach emotionally from people we care about, and often this leads to evaluating the relationship altogether, but if you want to save yourself some heartache and increase your emotional health, detaching is the way to go. Still love them, be supportive, but for you, keep yourself patient and quiet, forgive them, and go about your business. Getting mad and venting and blaming them for ruining your day is not taking responsibility for your own feelings, and thus not taking care of yourself. (And possibly making others who have to listen to the venting miserable.)
Later, when you are able to talk to the person about the event, it's much more productive and adult to state how you felt about the situation, and ask for what you need going forward. "I felt really upset when you didn't call as you said you would," not "you made me so mad when you didn't call!" "I would like you to follow through on your promises, or communicate with me if you can't, rather than leave me wondering what's going on." Being calm and clear will get you farther with them than shaming them or just venting about your anger.
Events happen. Feelings happen. Events become facts. Feelings pass. Deciding how we want to be and feel in each moment regardless of facts or feelings helps our emotional health and quality of life.