Please, don't tell someone, but sometimes, if that imagined conversation is very important, I make facial expressions...Fortunately, I am usually at home at that time, so people can't say :"Uuuu, she is..."(pointing finger in their head)
Mine is more like hand melt down. I believe a friend described it best "Rearranging Gravity". I throw them around like the scientist in Back To The Future. :mp:
I tend to change perspectives throughout the day. Watching things around me trigger hypothetical situations which play in my head. I make attempts to stay in the present moment but it is difficult. I like to look at things from different angles, and may have 10 or so points of views going on at once. But that isn't much; I know some who can have 100s of them at once. I'm working on improving my capabilities.
Yes, I have very deep conversations with people in my mind, and they are basically compulsory. I'm sure there are a few people from my high school who think I am insane because I looked like I was talking to myself.
I often go over an imagined conversation with someone I'm likely to meet up with in the upcoming days. I also tend to make up a conversation with someone I'd like to see in the upcoming days .
They tend to be good natured, although there have been times when I've been angry with someone and I'll have a heated imagined argument (of course I would rarely, if ever, actually confront the person who has caused the trouble).