Gladwell presents a wonderful collection of stories that focus on how the underprivileged Davids of the world are not so bad off as we usually think in their fight against the Goliaths. Instead, whatever their disadvantages are, those very disadvantages often provide the perfect circumstances to beat excel. From physiological issues like dyslexia to life events like losing a parent and even the way in which authority is presented to us. Each of these would seem to seem to reduce one's chances of success but those who suffer them and persevere are stronger than those who never face such challenges.
Interesting tidbit: The biblical Goliath was likely nearly blind.