Great people

As I watch this program in BBC on nelson mandela I cant help but wonder what is it that makes people great?????

Circumstances
Ability to Deal with various circumstances...
Opportunity
Ability to sieze the opportunities and capitalise on them
Passion
They are extreamly passionate …about the cause, about their work, about their beliefs
Need
Ability to understand needs..of self and of people around him

I am sure there are many more ….will add….