I've had a lot of sleep paralysis experiences (mostly in the early morning), and yeah, for me they're definitely mostly negative and frightening, nearly always as far as I can remember involving either a sense of an abstract but notably "evil" (though the words I feel would describe it the best would be "malevolently oppressive") presence, either directly at me, in the doorway, or somewhere right outside the room, or the feeling of somebody sitting on top of me or holding me down and preventing me from moving. A lot of time these experiences happen at the end of a night of repetitive nightmares as well. Sometimes I feel as it is triggered by me waking up "in the mind", so to speak, and really not wanting to go back to sleep again, but then not actually being able to wake up and having to struggle against my body not moving while drifting in and out of "dreaming". Occasionally it will be accompanied by repeated dreams of me being able to get out of bed before realising I'm actually still stuck in bed, unable to move, repeating the same thing over and over.
It is definitely some of the most lucid dream experiences I've had - during them, I always feel completely lucid and aware (though when I think back at them when actually awake they're just as easy to see that they're dreams as ordinary dreams are) in a way that is completely different from how I feel during ordinary dreams and nightmares. However, I also don't experience any sense of control over what is happening in the dream like how most people describe "lucid dreaming" (although I am torn about what people say about "lucid dreaming" in general, feeling that people seem to be exaggerating the experience vastly, as my own experiences with what I feel is the most like what people describe "lucid dreaming" to be like is more like "dreaming that I have control over my dreams" than actually having control over my dreams).
There have been times when I've experienced something sleep paralysis-ish of a more neutral nature, which mostly involves me doing the whole "feeling I can't move -> feeling of desperately struggling to move -> dreams of waking up and going about my business -> sudden realisation that I'm just dreaming and still can't move" circle except with a feeling of extreme unsatisfaction rather than dread. These usually happen if I've laid down and fallen asleep by mistake in the evening or afternoon though, and I'm not sure if I stay asleep long enough for my body to go into the actual "cease movement" stage during what is essentially overlong naps, so I'm not sure if those are cases of actual sleep paralysis or just my dreams being weird. I do have the same "dream of waking up/realising I'm still asleep" routine without the whole feeling of not being able to move, so I know there's at least a difference in experience between the two, however.
But yeah, the ones that happen in the morning are a lot more intense and I can't remember any which haven't been scary or dreadifying. Usually I am filled with a prolonged sense of fear even after finally waking up from them (when I can actually realise that they were dreams), but it has never been bad enough that I've feared going to sleep again the next night. A lot of times the memory fades in a few hours just like any other kind of dream.