From The Art and Popular Culture Encyclopedia
Anger is a (physiological and psychological) response to a perceived threat to self or important others, present, past, or future. The threat may appear to be real, discussed, or imagined. Anger is often a response to the perception of threat due to a physical conflict, injustice, negligence, humiliation or betrayal among other contentions.
Common factors that can predispose one to anger include fatigue, hunger, pain, sexual frustration, recovery from an illness, or the use of certain drugs; hormonal changes associated with PMS, birth, and menopause, physical withdrawal, bipolar disorder. Research suggests some individuals may be genetically predisposed to higher levels of anger. However, generational behaviors relative to primary care givers' responses to anger actually have a much larger influence in "predisposition" to anger.
Intensity of anger
Many words in the English vocabulary describe various forms of anger that differ primarily by their intensity of passion and arousal. Here is a partial list, arranged in approximate order from the least to the most intense: annoyance, miffed, irritation, frustration, sulking, exasperation, offended, indignation, incensed, pissed-off, outrage, ire, livid, rage, fury, ferocity, and acrimony. One of the higher forms of anger is wrath, which is classified as one of the Seven Deadly Sins in Catholicism.