We all already have sleep paralysis; it's just that we're not usually aware during the sleep paralysis phase. It's the "being aware" during sleep paralysis that is what is disturbing to some people. We usually wake up after sleep paralysis has worn off. But some people become "conscious" during sleep paralysis and try to move their bodies, leading to weird alien abduction and rape dreams -- since you know what's going on with your body, you shouldn't have this problem.