I'm another one who memorises number plates...

Coat hangers all have to be a certain way and all the hanging clothes facing the same direction

I also like to count things to find the middle (e.g. the middle curtain in vertical blinds)

I like the dishwasher stacked a certain way - I swear DH purposely puts the bowls where the plates are supposed to go...

I know there are heaps more but I can't think of them for now.