If you think that Frankenstein was a dim-witted green monster with a flat head, bolts sticking out his neck and moved slowly in a mummy-like fashion, then please dismiss all such notions from your head as that vision is highly inaccurate.
Without spoiling it too much, the monster was not given a name and Frankenstein was the name of the scientist who made the monster. Another mistake that some people make is in giving Victor Frankenstein the title of Dr. Frankenstein, as he never completed his studies. As for the monster itself, it was yellow, moved with immense speed & grace and was extremely well-spoken, having learned English from, amongst other thing, Paradise Lost.
The book begins very slowly. There is a lot of background detail given that doesn't really add much to the story and by a quarter of the way through the book, I was considering abandoning the book. Thankfully I didn't, for as the story continued I was drawn in to Shelley's world.
The tale touches on themes of ethics in science, love, rejection, denial and a huge dose of revenge. Undoubtedly the best section is the first prolonged conversation that Frankenstein has with his creation. While some sections are tough-going, I would highly recommend this as a classic of literature, and the best antidote to considering Frankenstein as anything like Fred Munster.