My worst dream type is one where I'm looking for someone extremely hard and can't find them/reach them. My brain likes to always add in a sickening feeling of loneliness or abandonment and sometimes confusion or over-stimulation so that I also can't think. It won't even necessarily be what the dream is about.
Sometimes the dream will be extremely crowded with almost everyone else I know, except for the one person I'm looking for, or really any plot that has nothing to do with being lonely or abandoned. When that happens, it's like a dream in a dream, the same "dreaming while awake" feeling you might get from being depressed, but even more so because it's almost as if you can sense the main dream plot and feeling of loneliness and abandonment "hiding" under the overwhelming amount of dream people interactions and ridiculous dream world events that are happening.
I have that same feeling too! But it happens while I wake up from the dream, not part of the dream, in that little gap of what is normally nothingness while you switch from dreaming to awake. It's like the dream ends, there's a second of silence and black, then it fades into a light grey almost instantly, it feels like I go from stillness to spinning or flying forward insanely fast, and my ears become overwhelmed with sound like wind or static and there's always a feeling that there's millions of people growing around me who are murmuring, whispering, laughing, screaming, and plain talking, but it all gets so loud so fast, and then I burst into the real world with a gasp and my heart is beating so hard you can see it.
I apologize if that was a confusing description. My dreams, when I have them, are extremely elaborate and usually feel more real than my reality. They dig in to my deepest emotions and perception, and have countless layers of feelings and plot lines that can even contradict themselves while still happening. I love them, but sometimes I hate them.