Anger is a negative feeling, and when it comes in frequencies, and intensities, and durations, and in the normal range, it can be quite healthy. Unfortunately, when it becomes really intense or really frequent, and it's paired with behaviors that are problematic, if they're aggressive or uncooperative, they can cause big problems and people can run into having anger management issues.
From a physiological standpoint it activates our body to prepare us for dealing with a threat. So what that means is, like the fight or flight response it engages the sympathetic nervous system. And what that's really doing is preparing our body to handle a physical threat. So glucose energy is going to be pumped into the arms and legs so that in the case of anger, we're prepared to fight off a potential predator or arrival in our tribe. Our pupils are going to dilate, which is going to allow in more light and allow us to stand for threats that are potential dangers to the organism. So when anger is used in that way, and it's fairly short, it's quite healthy. But in our society often times we're having that kind of a response to threats that might be a threat to our ego, or from just simple frustration if we're in a traffic jam. And when that's the case, that kind of physiological response doesn't really get any kind of release, and we often have to suppress it, and it can cause all kinds of physical health implications.