My super black pastel only hisses when I lift his hide off of him and then rub his side so he knows I am there. He lets out one hiss and thats it he never strikes or goes in the "S" position. He is one of the tamest snakes I've ever had. If he sees me before I go in the enclosure he's absolutely fine. I think lifting that hide and going from total darkness to being exposed and woken up startles them no matter how laid back the snake is.