"It is our custom to say that someone is "lucky" or "unlucky" if they meet with fortunate or unfortunate circumstances, respectively. It is however, too simplistic to think in terms of random "luck." Even from a scientific point of view, this is not a sufficient explanation. Should something unfortunate happen, we immediately think, "Oh, how unlucky!" And yet this is not sufficient to explain what happened- there must be a cause. We seem to call "luck" that factor which overrides external conditions to bring about a positive situation. But that too is a cause; it is an inner cause, which we call "merit."
~His Holiness the Dalai Lama