Crew members should know that nervous fliers are well aware of the stress that accompanies flying, thus a simple act of kindness
may alleviate a great deal of worry. An obvious habit of flight attendants is to say “hello” to passengers as they board the aircraft.
Although the crew does this just out of courtesy, there is another good reason for them to treat passengers well.
The reason flight attendants say “hello” is to assist them detect whether a customer is sick or even intoxicated.
I get it, a couple beers at the airport bar before takeoff is par for the course, but being kicked off the aircraft is the real deal when it comes to alcohol consumption.