Groups

This is a topic I have been interested in for some time. 

There are certain groups of people that seem so organized. So determined. So goal oriented. So on mission. It amazes me every time. 

Right now in my own country, there is a group/tribe that are 5% of the entire country. They were in power for over 30 years before the current prime minister took over. Now against all odds, they are marching towards the capital city to take over the government. No one expected them to go that far. But they have made it. 

Despite the meaning of what that coup means to my country, a part of me wants to understand their drive. What is it that makes any group so united, so effective, so indestructible? 

I wonder about this type of drive being used for something other than war. What if all African's had this type of execution to remake Africa - an independent self sufficient continent... having full control of their resources? What if all black people dispersed all around the world(voluntarily or otherwise) came back to Africa with this singular mission? 

I want to understand this. 
I want to understand why we fight. 
What makes people that look alike, have similar cultures and values - hate each other so much.