Games : What happens when you reverse time in Animal Crossing New Leaf?

I just got Animal Crossing New Leaf.

I only play very late at night, so most shops are closed and the residents are sleeping.

So I have decided to change the game's clock (at startup) and add about 8 hours.

Then I enter the game, and do my stuff.

My question is: if I ever want to fix the game's time (revert it to 8 hours back in time), what could be the negative effects?