Beam Me Up, Scotty!: "It's alive!" was never said in the original book. The original monster was more of a Genius Bruiser than the Dumb Muscle that he is typically portrayed as. And Fritz (the hunchback that said "It's Alive!") was nonexistent until the movie.
Creator Breakdown: Many literary historians consider the monster's creation scene in Frankenstein to be an allegory on childbirth. Months before writing the book, Mary Shelley had given birth to a premature, deformed illegitimate child who lived only minutes. Victor Frankenstein's misshapen, partly-formed 'monster' is created in 'filth' and when first brought to life is jaundiced, as most premature newborns are. This allegory may be less obvious to us because most movie adaptations don't follow Shelley's text that closely and turn the creation of the monster into a more scientific and less earthy event than Shelley imagined.
One-Hit Wonder: Only one of Mary Shelley's novels is well-known today: Frankenstein, or the modern Prometheus. Although she was taken very seriously in her day, nowadays it's either Frankenstein or being the wife of Percy Bysshe Shelley (even though it was her efforts after his death that kept him from being considered a One-Hit Wonder)...