The other day I was listening to a friend tell a story about his father. He recalled how at Christmas time his father would separate the old fashioned tinsel and place them on the tree one strand at a time. Hearing this small description reminded me of a writing exercise where you try and use one short story to completely characterize a person. In this case, I can clearly visualize my friend's father as a meticulous and extremely patient person.
It's a great exercise for creating characters that are fully fleshed out though not only dialogue and appearance but action and motivation as well. but it's tough to do. People are so mulitfaceted, finding one story to sum up all the parts is tedious.
Of course this begs the question, what story would you use to characterize yourself? It's not easy, is it?