I think it’s rising to the challenge, doing something very difficult, which benefits a person or persons in an intensely profound way. It’s not something you can do all the time, but fueled by opportunity.
Helping people and enriching their lives on a day-to-day basis is not being a hero, it’s being a decent person (and should be a higher priority than heroism).
Heroism is that one moment that endeavors to shatter the concept of the purely-self-serving organism and brings great personal cost or risk in order to fight impending calamity on others. It is sacrifice.
