I am a big fan of "Young Frankenstein." It makes me crazy happy laughing every time.
I had, of course, always noticed the similarity between the scenes in it and the original Frankenstein movie.
What I did not realize was that there is a movie called "The Lady and The Monster" from 1944 based on H.P. Lovecraft's story "Donovan's Brain" that explains where the Teri Garr and Cloris Leachman characters come from. Dead. Ringers.
Young Frankenstein just got funnier to me if that is at all possible.
Knowing that, I'm going to guess that there is a movie out there that explains the rest of the scenes that don't connect to either of those movies and my mission is to find it. (without cheating on Google or Wikipedia)
I realize that my partial attraction to these 1940's horror flicks is that I just skip the Mel Brooks/MSTK3000 step and they make me laugh because I realize how funny they would be if someone WERE parodying them.
If you are a "Young Frankenstein" fan and have not seen "The Lady and the Monster," I strongly encourage you to do so.