compassion to anger

What causes anger? Krishna says in Geeta "kamatkrodhotbhijayayte" when some wish of ours is not fulfilled we get angry. OK then I have some questions .....

• Does it serve?
  
• why does senses ask us to get angry?
• is it programmed in us?
  
• at what level does it serve a purpose?

Yes... I understand it's too many at a time... but they are all so connected..I could not stop asking them all at once. My line of inquiry is that if it does not solve a purpose why has it been designed in our system ?
At animal level we see that anger has a purpose it takes the adrenalin and prepares the body to a level that we deliver our best. And one of the most often portrayed emotions in arts, movies, plays is the emotion of anger. At human level too it takes us to the basic nature of attack when some wish of ours is not on the path of being fulfilled. And it apparently solves the problem.. it creates an illusion of problem being solved due to the outburst. The pressure inside is released... so there is a relief.
Now lets go back to situation that led to the anger. We desired... and it did not happen... but why? our karmic cycle did not permit it! thats how we explain things in life. The things that our karmas deserve comes to us. So when we did not deserve but had the want for it, it did not come. Can it come to us by the action of anger? yes it can ... if we are ready to pay in terms of our punyas... so Rishis used to give shaap to people who did not behave in a way acceptable to them. As a result of which they used to loose punya and had to go to do tapasya again! So we are losers when we get angry. Now what if we do not have enough Punya... then we are losers all the way! Waisting punya in the spiritual world and the losing confidence of people in the material world.
So a naive brain would react in anger which a sophisticated one would not. Though the intent of the person may remain unclear and possibly account to a later accumulated outburst or may be subside through cogitation and realigning of the thoughts.
But is anger bad to the material world? Once a mahatma replied to a pupil that anger of knowledgeable does good to the society and that of a fool creates nuisance.