There are two types of waiting room. One is where individuals leave for appointments one at a time, or in small groups, for instance at a doctor's office, a hospital triage area or outside a school headmaster's office. The other is where people leave en masse such as those at railway stations, bus stations, and airports. These two examples also highlight the difference between waiting rooms where one is asked to wait (private waiting rooms) and waiting rooms one can enter at will (public waiting rooms).