Highly Sensitive People think deeply about things that have happened; conversations they have had, and even about upcoming events.  We take in so much information, that we explore multiple aspects of things we've experienced.  Sometimes this means that we play "Could have, would have, should have" and it's usually not in our favor.  We tend to be hard on ourselves and beat ourselves up wishing the conversation might have gone differently.  Sometimes we need more time to process, and don't say what we want to in the moment.