It's not logical, it's arbitrary. When describing when things happen, I think about the month first as it confers context, then pin point it to the day, then clarify with the year. Which is most similar to the way you would use a calendar. When scheduling an appointment you look for the month first the vast majority of the time.

I agree going from smallest to biggest makes sense. I was just questioning how it doesn't work. Which obviously it does. I can look at 6/12/15 and know it's the 12th day of June. Now the metric system on the other hand is far easier to understand than out current system, but logistically converting everything over would be a nightmare at this point.