OK, this is completely random, but sometimes when I'm reading about props and other sci-fi stuff, I'll see a word and just read it without really considering how to pronounce it. Then, if I'm trying to explain something to my wife or friends, I think, "OK. . . so how do you actually say that word??"
One example that comes to mind is GRAFLEX. Is it pronounced like "Gray-flex" or more like "Graph-lex"?
Any other examples out there?