Before I saw DV and started working on my dream recall, I always thought there were two main types of (non-lucid) dreams. Regular ones=not scary, nightmares=scary.

But now that I dream more, I've found that I have lots of "scary" dreams, but I only rarely have nightmares. For example, in one dream (long story short) there was a person who killed me. When I died the dream started over and she came after me again, and each time it started over I tried something different to get away but she always got me. At the time it was scary, but I wasn't actually scared... if that makes any sense. Then in a another dream I'd left my cat in a box for too long and she went blind, and I completely freaked out, so much that I became lucid but I was still freaking out then, and when I woke up too.

Has anyone else noticed something similar to this? What is it that makes the difference between a "regular" scary dream and a nightmare?