Q: Every time I see people arguing or fighting, I get nervous. But whenever the confrontation is directed towards me, I'm never nervous and always ready to fight. Why is that?

A: 
It seems that everyone I talk to has a slightly different answer to how they feel right before a fight.  There are some common themes though -- dry mouth, butterflies in the stomach, wooden feeling limbs -- all signs of impending fight or flight syndrome.

When the stress builds, you start to get significant physiological changes happening in your body:

• Loss of peripheral vision due to blood flow away from the eyes. You start to get tunnel vision and you focus on the threat .

• Pupils dilate in an attempt to get more information to the brain.

• Your eyes widen in order to open up the field of view.

• Blood moves to major organs and away from your skin.

• You may experience auditory exclusion.

• Decision making (therefore your reaction time) is hampered by hormones inducing high heart rates.

• Fine motor skills diminish as your heart rate increases. 

For those who are untrained in martial skills, there is a period of denial and then anxiety sets in.  For those who ARE trained in fighting, there is a period of anticipation -- a period of wondering if or when the fight will start.

The universal physiological responses listed above  that accompany combat is often labeled "fear".  If you are untrained, then being afraid is a good thing.  If you are trained, then you might be mistaking your body's preparation as nervousness, doubt or fear.

In your case, you might be feeling that you don't have control of the situation when you are on the outside.  I will commend you for staying calm while YOU are the one in the barrel.

The people that seem to be able to stay calm while in the center of the storm are the ones that have been there many times before or they are dealing with the situation as a "professional" (cops, bodyguards, bouncers) and are more detached from the ego thing.