Robert Cialdini’s Influence provides a particularly enlightening example of the human tendency to hang on to the words of the experts:

There’s a funny story about a doctor who ordered ear drops to be administered in the right ear of a patient who was suffering from an ear infection. Doctors are notorious for poor handwriting skills and using shorthand notations. In this case, instead of completely writing out “right ear” on the prescription pad, the doctor abbreviated and instead wrote “R ear.” The nurse on duty received the prescription with the instructions from the doctor and promptly put the ear drops on the patient’s anus. She knew it was an ear infection so putting the ear drops on the patient’s rear end made absolutely no sense, but she never questioned the instructions because they came from a doctor. The patient went right along as well. No one bothered to question the misinterpreted instructions because they came from someone in a position of influence.