I have a tendency to make comments out loud even if no one's within earshot - especially at work and especially if no one's in earshot. I even do it at home when I'm doing housework. Just my kitties and me. If people are around, I'm a bit more aware about what I let slip out. No, it's not Turrets.
I have a tendency to play out entire conversations in my head be it past or future. Heck, even present when I have enough time to think while others are talking. Sometimes, while I'm conversing in my head, I'll catch myself audibly saying the last few words, my response to a ficticious question or even laughing out loud in response to a scenario, either real or imagined.
My question to other INFJ's:
Am I the only one who does this??
I get really self conscious when I realize I'm reacting to myself. I'm sure my roommate (ISTJ) thinks I'm slightly crazy anyway.