To some degree, we all are creative in the small-c way, doing things that enrich our own lives but do not receive recognition from the outside world. Big-c creativity is different -- it produces ideas that "push our species ahead".
Big-C creativity is rare. Defining it is impossible, because every definition seems to over- or underconstrain something essential to creativity from our own experience. But Csikszentmihalyi asserted that society values Creativity for its ability to transform people and cultures, and that it drives creative people to "pursue to completion" the creative act.
He goes on to mention ten characteristics of personalities of creative individuals (some surprising points) and finally ends with a question that I ponder often : "If the world is changed by a rather small number of contributors, where does that leave the rest of us?"
This is one of those questions that we could probably never answer, but I still wonder what role each individual plays in this world. When we think "individuals", we think of people who have changed other people and the world in a profound way (whether positive or negative) such as Mahatma Gandhi or Hitler, but what about those we never hear of? What is their "role"? To consume? Or to just be?
Coming back to creativity, why is it so difficult to define it? What makes one person more "creative" than the other?
My view is that it comes down to "thinking differently" and "making things happen". It is this combination that is potent. Leave out one of these factors, and that potent is lost.