Me, working through a problem: "So, that means..."
Girlfriend, coming in from outside: "Who are you talking to?"
Me: "I talk to myself. You know that."
Gf: "Oh right. You also whisper to yourself, which is scary."
Me: "Scary?"
Gf: "It sounds demonic."
Which, to be fair... Evidently, my internal monologuing gets quite a bit vocal even with other people around.