The only thing we really control is ourselves, and every time we get angry, we've allowed someone else to manipulate us by pushing our hot buttons. When we feel emotions rising, we might want to ask ourselves how we are playing into someone else's game. Are we really that easy? If we allow ourselves to act unconsciously, then yes, we are.
One of the benefits of meditation is creating space within ourselves to be able to observe how our own thoughts and emotions arise. When we learn to separate ourselves from such phenomena, we gain greater control over our ability to choose our own direction for ourselves.
Think of difficult people as challenges to our own self-control. There are many who will test us simply because their own lives are uncontrolled. Their sense of self-worth is validated externally, so by provoking us they feel as though they exist and have importance, forcing the world to acknowledge them. Calmness may fluster them because they don't understand it. They don't feel at peace within themselves. If they can get others to match their own internal state, then they feel a sense of recognition; they live within their own world of stormy emotions and so invite us to join them there.
Conversely, if we remain calm and weather their outbursts, we may be able to plant a seed of calmness within them, creating an anchorage against the pain of being tossed by what they themselves cannot control. At the least it may allow their own rage to expend itself, until they are too tired or bored to continue their assaults against ourselves. Think of advice given for dealing with aggressive animals. If a dog or even a bear charges and we run, we become a moving target to be taken down. On the other hand, if we stand in place (dogs) or curl up in a ball (bears) we have a much better chance of surviving.
Cats that run from dogs will be chased and killed if they cannot escape. On the other hand, those that sit immobile may still attract initial attention, but after nosing around, a dog will generally get bored and leave. I've witnessed both. Why do deer freeze when caught in headlights? It's because that is their defense against drawing predators into the chase.
Aggressive humans are also predators. Think of them as emotional vampires who feed off the response of their victims. They may seem strong, but in reality their weakness is their need to feed off of others. If they do not get the reaction they seek, they are lost.
I've been in dangerous situations where remaining calm defused assault, and I know women who have avoided rape in the same manner. Even if we have to fight, it is better to do it with a clear head than one clouded by fear. Fear has its place as a warning, motivating a response, but do we want others to be able to use it to pull us into their trap? If we consciously note rising emotions, we can deal with them before we hit crisis mode, and that generally is the better response.