Frankenstein

Frankenstein was a person. He was a scientist. He created a being made from the dismembered remains of corpses and brought to life by electricity. That being was called a monster, but it was never called Frankenstein. (At least, not in the novel where this all happened.)

I find it amusing when people call the monster Frankenstein just because it's kind of wrong. I also find it frustrating because when the monster and the man are both called Frankenstein, it makes it very difficult to talk about one without going through the trouble of explaining more specifically which one is meant. 

If nothing else, recognize the importance of names and naming. If people don't have something they can latch onto, they will either make up a name on their own, or they will simply not talk about it.