“It was a dark and stormy night” has entered the English language as the canonical opening sentence for bad novels. Snoopy in Peanuts traditionally starts his novels that way, and Terry and Neil used it on p. 11/viii of Good Omens as well.
I never knew, however, that the phrase actually has its origin in an existing 19th century novel called Paul Clifford by Edward George Earle Bulwer-Lytton. Someone kindly mailed me the full opening sentence to that novel, and only then did I understand how the phrase came by its bad reputation:
“It was a dark and stormy night; the rain fell in torrents — except at occasional intervals, when it was checked by a violent gust of wind which swept up the streets (for it is in London that our scene lies), rattling along the housetops, and fiercely agitating the scanty flame of the lamps that struggled against the darkness.”
There even exists a Bulwer-Lytton Fiction Contest, in which people try to write the worst possible opening sentences for imaginary novels. The entries for the 1983 edition of the contest were compiled by Scott Rice in a book titled, what else, It Was a Dark and Stormy Night. I am told that there were at least three such compilations released.