I work for a big multinational company and Jira is set up to have the week starting on a Sunday. Where I work, the week starts on a Monday. The people in charge of our system have said it isn't possible for some users to have the week start on Monday or any other day of the week) and other a Sunday.
Is it really true that the start day of the week can't be changed for sub-sets of users? Around half the world starts the week on a Monday, around half on a Sunday and there are others who start the week on a different day.