Anger is usually a response to being threatened. When you get angry, ask yourself what you are protecting and then ask yourself why you are protecting that.
If you are protecting a belief, the anger can be pretty intense because the ego feels attacked, and it could be a sign that the belief is an illusion that is ready to be dissolved. Our beliefs are held in the ego. Belief is created to build an identity, but when that identity shifts, the ego can feel threatened and act out in anger.
The ego does not like change. It only likes attention (good or bad). But the healthy ego knows it can survive the change of beliefs and spiritual growth. The wounded ego needs to hold on to what it believes, or else it will feel like it is dying.
Many people going through spiritual awakening have dreams of death or feel like they are dying. It is because the ego is a drama queen who convinces the self that the 'end is near.'
Being overly attached to beliefs can be toxic to self and all of life. Being aware of what we believe and why we think that way is a healthy step toward awakening.
The healthy ego knows that change is important, and new perspectives are needed as we grow. We can nurture a healthy ego by examining why we think and feel the way we do.