As a nurse in a 'county hospital' we see some of the same rude behavior. I guess a few just love to have someone finally under their thumb. The kicker is the occasional person who will tell a nurse "you have to do ____, I pay your salary!". Did I mention I work at the "county hospital"? Most people DON'T pay for their medical care or have insurance. They are on Medicare or Medicaid. That means that taxes are paying their bill. Or as we say "we are paying our own salary"
Also, it isn't a good idea to be rude to someone who controls your pain meds or the food you will be eating.