I have quite a few :/

Car stereo, tv, and house radio volume must be on evens at all times. the tv is on 20 if we are all watching tv, 16 if the girls are watching and 12 if its just me.

When shopping I never get the item from the front on the shelf, always have to get one from behind.

Milk use by dates must be even, unless they are special dates like birthdays etc, then they must be bought.

cant deal with dripping taps either..

The list is great here.

OH and MIL has the peg thingy too. All female items must be hung up using pink pegs, boy for male items, and the unisex things like towels and sheets must be hung up using white pegs. (I have lots of fun messing with her system whenever we are there :LOL: )