It wasnt scary at all for me until they started threatening to kill me. Now though that doesnt really scare me much either. I smoked a joint last night and a voice said 3 times "Kill me im evil" for some reason that got my heart racing like mad (partly to do with the weed). It also said "Im lucifer incarnated" that scared me a bit but since I dont even believe in the devil and wouldnt give a shit if i did it was only a brief shock like when someone surprises you.
When I smoke weed im scared of everything so hearing voices does scare me the odd time. When I hear them sober it isnt half as clear and doesnt bother me at all. I never hear them after taking schooms or psychedelics but after staying up days I hear them loud and clear but its not scary no matter how fucked up the things they say are.
Then again this is all drug induced schizophrenia im talking about. Ive never experienced the real deal.