Well, Sunday is more of been weekend than the week day has it is a day or rest and no work. I think the week day should be days from Monday to Friday. The days one get to more active with work activities. I understand it might be a little confusing due to the fact that first day of the week happens to fall on that day. While some think of weekend has the closing of the week or something. It is all about perspective. At the end of the day, it what we chose to make of it.