We just need to think logically. Most people sadly don't even think as far as the fact that our year is the result of our planet orbiting the Sun one time.
Our calenders can, logically, not affect the universe. We can plot dates into them, but even if we did not have calenders, the events would still happen at the same time. The physical laws are beautiful and we don't need any strange calender dates or tooth faries to explain events. Sometimes, events will happen on special dates, but it's just as likely that they will happen on the normal dates.