Neville shook his head in frustration at Harry. "No, it isn't like that. Rituals only cause pain if they are designed to. Harry must have known he'd have to cause you a little bit of discomfort, because all of your pain had to pass out of your body at the same time. So he got it over with as quickly as he could, to minimise it for you, probably overloaded you with euphoria just prior so it would act as a positive drag. Why didn't I notice it?"