When reason ends, then anger begins. Therefore, anger is a sign of weakness. (HH Dalai Lama)

If subconscious anger had a parallel in Buddhist writings, it would have to do with what is called mental unhappiness or dissatisfaction. This is regarded as the source of anger and hostility. We can see subconscious anger in terms of a lack of awarness, as well as an active misconstruing of reality.

If there are sound reasons or bases for the points you demand, then there is no need to use violence. On the other hand, when there is no sound reason that concessions should be made to you but mainly your own desire, then reason cannot work and you have to rely on force. Thus, using force is not a sign of strength but rather a sign of weakness. Even in daily human contact, if we talk seriously, using reasons, there is no need to feel anger. We can argue the points. When we fail to prove with reason, then anger comes. When reason ends, then anger begins. Therefore, anger is a sign of weakness."
from 'The Dalai Lama, A Policy of Kindness'