I don't know that it really was, but it seemed like a good starter at the time. Actually, some think that it's the worst beginning ever: Redundant. Nights are dark by nature.
But I like it. Sets a good tone, even if you are the nitpicky kind. But I think that those who dislike the sentence don't actually like a sentence, but dislike what it starts: a story that actually gets told. You'd be surprised how many people will criticize a story but not tell their own. There is a surplus of people willing to talk and criticize, but a shortage of those willing to do the work and just tell the story. A story seen through to the finish has to have a starting point, no matter how bad a starting point it is. There are billionaires who start with nothing and cooks who start with the most raw ingredient, so must each story be told from the ground up.
So start with the worst sentence imaginable. Build from nothing. See what the dark and stormy night has to