Hard work and working hard makes a person dig deep and discover what they are really made of. I have a lot of respect for those who work hard everyday to just get by or for those that set out to work and reach their goals.
Hard work encompasses so many character traits. Facing adversity develops those traits and builds coping skills. Perseverance, grit, zest, curiosity, trustworthiness, courage, respect, responsibility, gratitude, humility and more.
John Wooden says, "Sports don't build character, they reveal it." This can be found when a team or athlete faces adversity and how they cope with the challenge in a selfish way.
BUT, I respectfully disagree with JWooden, if and when an athlete or team takes a challenge and works through it, that is when character is being developed.