Often people are programmed to have pain because of things they have heard or been told a practitioner. "Never bend at the waist" means the onset of pain is a sure thing when they bend from then on, although it may never have caused pain before. Someone says that sitting compresses the lower end of the spine-so, of course, it's got to hurt when you sit. Standing in one place, lifting, carrying all have a bad reputation and will quickly be conditioned into a patient's pattern.