Have you ever wondered why (in the United States) our date format is a mismatch of significance?
"Significance" in this instance referring to the weight each section of the date carries: Year(Y) being more significant than Month(M); Month more significant than Day(D).
A logical date format would progress from either least to most significant (D-M-Y) or most to lest (Y-M-D). Our format is (in level of significance) Middle-Low-High.
According to the wikipedia article "Date format by country" – and ignoring countries that use multiple date formats – there are approximately:
3,200,000,000 people in countries that use D-M-Y
1,500,000,000 in countries that use Y-M-D
310,000,000 in the United States using M-D-Y
If you ignore the "logicalness" of D-M-Y and Y-M-D, for most people in their daily lives, our format would seem to make the most sense (totally biased opinion).
If we need to know about something coming up in the future, the Year can be pretty safely assumed, and if not, toss it at the end. In many cases the argument could be made that the Year is the LEAST significant part of most dates.
Putting the Day before the Month (as in D-M-Y) just seems bizarre. It would be like asking someone for the time and having them tell you "it's 35 seconds after 20 minutes into the 8th hour of the day."
All that aside –
I've come to the conclusion that the real reason we use the M-D-Y date format is because we, as a country, are incredibly self-centered, and that this is the only date format that allows us the chance to see our own birthday displayed on a clock twice a day.