Passengers can vary, such as language, culture, religion, education, habits, styles, etc. Have a different understanding of communication do not understand it. Passenger is the most difficult for the crew.
Passengers have different characteristics such as language, education, religion, culture, etc. It is understood differently. Communication does not understand so passengers are the most difficult for the crew.
the passengers there are differences such as language, character, education, religion, culture, etc., have a different perception, communication, understand. Therefore, the passenger is most difficult for the crew.