How do great fiction writers develop their plots?
They often put their characters into difficult situations and see what happens. They build tension, bring in difficulties and close out all the obvious escape routes. They then imagine how these characters would rise to this challenge. Et voila! They have a good sub-plot to add to the rest of their novel. By doing this repeatedly, they develop their characters.
Our legacy is the story we leave behind. Much like a novel, this story is as interesting as its sub-plots. Much like characters in the novel, we often grow and develop ourselves by putting ourselves in difficult situations. What we are capable of is merely the sum of the difficulties we have once overcome.
To build their characters, novelists put them in difficult situations. To build your own character is to do the same with your own life.