The quote below is from The Black Swan, and I rediscovered the quote in THIS great post from Jana Vembunarayanan where he discussed what he learned from the Big History Project:
"I am sometimes taken aback by how people can have a miserable day or get angry because they feel cheated by a bad meal, cold coffee, a social rebuff or a rude reception. We are quick to forget that just being alive is an extraordinary piece of good luck, a remote event, a chance of occurrence of monstrous proportions. Imagine a speck of dust next to a planet a billion times the size of earth. The speck of dust represents the odds in favor of your being born; the huge planet would be the odds against it. So stop sweating the small stuff. Don’t be like the ingrate who got a castle as a present and worried about the mildew in the bathroom. Stop looking at the gift horse in the mouth – remember you are a Black Swan." -Nassim Taleb