What is the origin of agency?

What I admire in people is agency. The confidence to not accept the norm and have the courage to change.

This is a different matter than confidence or self-doubt. Agency means you know this is not right and act on it. You know there should be a better way. You know you cannot wait for others to fix it. Along the way you have doubt, but not about the original "this is wrong," but about the methods and answers.

You know you must start the change and you do it.

The question is how can one improve agency? How can I buy it, like from a shelf of human capabilities at a supermarket?