It's dissociation from something, I have to zone out to talk otherwise I start panicking, I do it for anything I don't have to pay attention to continuously(and most of those, it allows for a sense of detachment in pressure-heavy scenarios imo :p but I guess then you have to be able to maintain some awareness while doing it and im still not entirely sure I'm talking about the same thing you guys are). Normal people do it when they daydream, ptsd peeps usually use it to accomplish something or maybe theyve gone through so much that they have to maintain that detachment from w/e.