Day 12 is something I am OCD about.
I'd have to say money. Like actual paper money.
As I've said before... I'm work in a bank.
I hate hate hate for the money in my drawer to be turned different ways. It drives me bonkers. I've gotten better though... when I first started (almost three years ago...wow) I would turn all the bills the same way, and then sort them by color. You know how like the old five dollar bills are white, but the new ones have big purple 5's on them? Yeah. It was bad.