Both.
Lucid dreaming is actually really fun, you're aware of what's going on and you can create/construct what is inside the dream, kind of like Inception but to an extent. If you do too much at one time or if you get too excited, the dream collapses and you wake up.
Sleep paralysis isn't fun at all. One time I opened my eyes and I couldn't move my body. I felt like someone was slowly walking towards my bed and I literally felt like I was going to die. So I went back to sleep LMAO