Researchers at Frankfurt University have found that
forcing oneself to be friendly or cheerful can shorten one's life; consequently, front-line customer service staff such as waiters, flight attendants and call centre workers who remain in contact with the public for prolonged periods of time suffer stress which can lead to depression and weakening of the immune system. Being able to lash out at those who piss one off, however, keeps one healthy:
"Every time a person is forced to repress his true feelings there are negative consequences for his health," said Professor Dieter Zapf, a researcher into human emotions.
The study tested students working in an imaginary call centre who were subject to abuse from clients. Some of the participants were allowed to answer back, while others had to be polite and friendly all the time. Those who stood up to clients had a rapid heartbeat for a brief period, but for those who had to remain friendly their heart was still racing long after the client had hung up.