The next level can be characterized with more magnitude than the first "stage" I described. You'll curse and put on a hostile facial expression. People may begin to notice.
The third stage is a more intense, and unrestained version of phase two. You'll clench your fists and yell. Adrenaline often will begin pumping, depending on your situation.
The last stage is what people refer to as rage. You lose control of yourself. Anything that comes in your way will often become a victim of a punch. In this stage, the conscious mind does not exist and cannot stop you from making choices, eg fighting. The most amazing feeling about this is the unrelenting strength that you receive from the pumping adrenaline.
Anger is truly an amazing and destructive emotion, it brings us closer to our true primal roots.
Anger is an active and passive emotion. When "active" an angry person can "lash out" verbally or physically at an intended target whether justified or not. When "passive" anger is often demonstrated in silence, sulking, passive-aggressive behavior (hostility) and tension.