Sometimes I have a conversation when I am beyond exhausted. I use all of the power and energy I have to stay awake and pay attention, but I am running on fumes and just can't maintain it. My eyes close, I slip in and out of consciousness. I start dreaming.
My dreams can range from the thoroughly bizarre to the incredibly mundane. And the early ones are usually mundane. They're just conversations with people. Nothing impressive, just shooting the breeze.
I'm not entirely asleep, though. I'm still trying to participate in the real life conversation. So I keep transporting between the conversation in front of me and the one in my dreams. The other problem is that I'm not usually aware that I switched from to the other. That's when the confusion starts up.
To the other person, a conversation about music and musicianship gets very quiet, then becomes about why a hot paint job on a car is really worth the money.
When you write, you are entering a different plane of existence. It is a world in which everything that happens there is real. When you stop writing, you go back to this world. Sometimes, though, you bring along some baggage. Writing can be a very real experience, as real as the most intense dream you've had. When you disengage from active writing, make sure you fully disengage. Don't bring any of that baggage with you. All it does is confuse the crap out of everybody else.