Different cultures have varying traditions of rest. Approaches towards the number of days of vacations taken each year, the length of the working day, which annual festivals should be treated as public holidays, siestas, work levels during Ramadan and so on are all taken on the basis of the culture and history of that particular country. As a result it is not unreasonable for a country with a Christian background to identify Sunday as their designated day of rest.  The work ethic of any country relates to their history as is reflected in the festivals that are given significance. Observation of Christmas or Eid or Cheoseok has little to do with the personal values of the individuals concerned but rather the historical norms of that society.