Premanand Maharaj Ji
Why do I get angry when people don't behave as I expect?
Anger comes from expecting comfort from others
Anger is born of desire, of wanting others to treat you as you wish. Stop expecting comfort from others and try to be agreeable to them, seeing Bhagwan in all.
The root of anger is desire. Anger arises from desire. The wish to get happiness from others is what creates anger.