Why we rage?

Ok, so as interesting and enthralling as the whole toilet project is going to be i'm going to need pilfer someone's digital camera as however much i love the traditional film format it isn't exactly conducive to easy computer viewing. So for now i shall start to use this blog properly as a forum for whatever i've been dwelling on this week.
So to start with a cheery subject, i've been wondering about anger. What exactly is this emotion all about, does it ever have positive consequences? As someone with quite a temper i'm not unfamiliar with the rising tide of blind rage but rarely has it propelled me to change things for the better. I can see that anger might be construed as necessary to motivate social change but does anything ever change whilst the anger still rages?
On the other hand, this week has been rather a swirling storm of anger from all directions in a certain group of my friends and aquaintances. Promted by the two major culprits in inciting anger: Lust and Revenge. But in the midst of this and being both the recipient of many peoples anger and having had my trust betrayed majorly i feel it completely unnecessary to get angry. It is as if an overload of other peoples emotions has laid bare the pointlessness of this emotion in achieving anything. So believe it or not i find myself being told that i must be angry in order to make others realise what they have done wrong, but surely if someone faces anger thay are much more likely to defend their actions then repent. Still pondering.