Most people don't actually view Monday as boring. Those that love their jobs or their businesses actually look forward to resuming their jobs after the week end break. While those that hate their jobs or consider it to be less fun are the ones actually seeking the beginning of a new week as boring.
Monday is just like every other week days. It's the activities that you engage in in each day that determines how fun filled or boring you day would be. But a boring person will always have a boring day regardless of the activities in the day and a happy person can turn a boring day into a fun filled day.
Who the individual is and his/her perception about such day also play major parts in determining if the day will be boring or interesting.