I found that after a few months on HRT I started to have dreams (often nightmares) that felt emotionally real to me.
Ones where I'd wake up in a blind panic after experiencing a full adrenaline dump, and would haunt me well into the day and sometimes for several days if the dream was particularly bad.
The fist time this happened was a bit of a revelation to me. I'd always puzzled that my ex could (and frequently did) have her whole day ruined by a bad dream.
While I was still running a Testosterone based OS I'd have the occasional bad dream, but within minutes of waking and sense of realness quickly faded.
By contrast, I've had almost all my cis female friends report having dreadful nightmares that would leave them on edge for the whole day or longer.
Now that I've experienced this myself it's really opened my eyes to something I would have written off as an over-reaction before. A dream in which my daughter died left me just about useless for two days, and emotionally raw for over a week.
By contrast, male friends who I've asked all report that their dreams lack much emotional realism, and that even the worst ones are quickly forgotten.
So what have your experiences been?