Ever since I was little, I have hated to have to say a movie or book title, or an actor's name, or something like that. It's like I'm embarrassed that I know the full name. It may be because I learned to read at 3 (taught myself watching Sesame Street) and was reading way above my level as a child, so I used big words, and other children made fun of me. So I stopped using the words in my head and started talking like the others.
For example, if my DH says "Whatcha watchin'?" I'll say "Some sci-fi movie" and then he will prod me until I tell him the name, and I resist it as much as possible. I don't know why.