Swami Sivananda, “You may ask me the reason why you become frequently angry. Anger is nothing but the modification of passion. When the passion is not gratified, it assumes the form of anger. The real cause for anger is ungratified passion. It expresses itself in the form of anger when you deal with the mistakes of your servants. This is an indirect cause or external stimulus for its expression. Raga-Dvesha currents are not thoroughly eradicated. They are only attenuated or thinned out to some extent. The Indriyas or senses are yet turbulent.
They are subjugated to a small degree. There are still undercurrents of Vasanas and trishnas. The outgoing tendencies of the senses are not totally checked. You are not established in Pratyahara. The Vritties are still powerful. There is no strong and sustained discrimination or dispassion. The aspiration for the Divine has not become intense. Rajas and Tams are still doing havoc. There is only a small increase in the quantity of Sattva. Evil Vritties are not thinned out. They are still powerful. Positive virtues have not been cultivated to a considerable degree…” (pg. 198, Concentration & Meditation)
Swami Sivananda, “Anger is a gate to hell… It is a modification of lust…If a man man becomes irritable for trifling things very often, it is a definite sign of mental weakness….” (pg. 191, Concentration & Meditation)
Swami Sivananda, “If a man wants to correct another man and uses slight anger unselfishly as a force to check and improve him, then it is called ‘righteous anger‘. Suppose a man molests a girl and tried to outrage her, and a by-stander becomes angry towards this criminal, then it is called ‘righteous anger’. That is not bad….He should be cool within and hot and impetuous outside. He should not allow the anger to take deep root in his Antahkarana for a long time. It should pass off immediately like a wave in the sea.” (pg. 190, Concentration & Meditation)