Courage is a commitment to something bigger than yourself. Fear is often considered the opposite of courage, but I would suggest that fear is an important part of courage. Courage comes when you are more afraid of the consequences than you are of failure, of injury, or of death.
People often do things that are considered courageous to others, but they themselves see as routine. So I would suggest also that it really depends on your perspective. The reason we see things differently comes from education and exposure. To the untrained eye, charging into a fire requires a lot of courage. To us, we know that we can do things like stay low, or shut doors behind us, or position a line at the stairwell to protect our egress. We train in fires and we go to many fires, so all of that helps us to maintain our own perspective. The danger still exists, but we have learned to live with it.
Our acceptance of the danger, however, should not be confused with complacency. Complacency is laziness; complacency is disrespect of the conditions. We may get conditioned to live with the danger near to us, but we should never underestimate its unpredictable nature. We may think we have all the facts, but sometimes we do not.