I don't have a clue why we do MM-DD-YYYY and personally I hate how dates are done in the west, to a degree.
For a maths course I've been taking at college, I never use MM-DD in my notebook because that and DD-MM are stupid in my opinion. I always spell out the month first to ensure I don't get mixed up. I honestly envy that some languages like Chinese and Japanese have an individual character to help distinguish between month and day.
Also, I would love if every country using the MM-DD or vice versa format could all agree on which format to use for everyday things.