I do this quite a bit. Also, when I'm at work and I'm struggling through/enduring involuntary interactions with my co-workers all day long I often laugh at how my unusual interpersonal behavior affects them. They take this laughter as genuine insanity or "crazy" behavior. They don't know how far detached I am from them and the person they are interacting with is not really there so to speak. I am far back from a distance watching. So yeah, I think it's funny how they (mis)interpret my behavior and take cues from my facial expressions and other non-verbal behavior to reach ridiculous conclusions.
But to them I'm laughing maniacally for no reason. And that, of course, is crazy. Everyone knows that.