That is a question posed by Robert H. Frank in his forthcoming book Success and Luck: Good Fortune and the Myth of Meritocracy. The main point of this book is to illuminate the major role which luck plays in our lives and then to flesh out the social and policy implications of that fact.
My view is more Straussian than Bob’s: I think we have to believe in a concept of meritocracy whether it is justified or not. (Do note that Bob covers a version of this point in one of his chapters, where he argues that reminding people of their good fortune makes them more generous; I still think society requires strong feelings of desert, and generosity often follows from a kind of false magnanimity about one’s good fortune.) But as always with Bob, this is a deep and stimulating book, well written too. You also learn a great deal about Bob’s highly interesting life, such as how he survived his heart attack, pulled out Cornell tenure at the last moment, and decided to track down his birth parents.
Anyway, the comment section is open: what is statistically the most improbably thing that has happened to you?