I remember our pastoral care professor in seminary saying: "Anger is a rational response to injustice."
Anger is meant to motivate us towards positive action, but when we don't get the hint, then anger takes on a destructive force within us. Anger is meant to be transformed into positive energy. When it is not, it becomes negative energy.
But, anger arises in us in response to many situations other than injustice. Anger often arises when we feel slighted or rejected, or when we feel envious of someone else. Anger can arise when we find ourselves in an uncomfortable situation that we don't know how to handle.
And, anger leads to angry words often, and at times to angry actions.
Most killings we deal with in court happen because of something stupid, because of conflict erupting over some hurtful words said, or someone's pride being wounded, especially when one or both were intoxicated. Anger moves directly into striking out. More on this later.