I'd like to start this piece with 2 quotes that complement each other:
"To add value to others, one must first value others." ~ John Maxwell
"Before you are a leader, success is all about growing yourself. When you become a leader, success is all about growing others." ~ Jack Welch
The bottom line here is: A good leader "Develops herself (or himself) and Develops others...that's what letter "D" stands for.
I believe that the best leaders want the best for those they lead by encouraging them to be their best. One sure way of helping people be their best is by providing them with opportunities (some of which may be challenges) to develop themselves.
I'm sure like me, you don't disagree with the President on this:
"The greatest leader is not necessarily the one
who does the greatest things. He is the one that gets the people to do the
greatest things." ~ Ronald Reagan