What's the most absurd 'life rule' you follow for no real reason?

I have this ridiculous rule: never take the first or last item from a shelf at the store. I tell myself the first is "too touched" and the last is " too lonely". It makes absolutely no sense, but I stick to it every time.

Does anyone else have weird little life rules like this? The ones that don't actually matter but you can't stop following anyway?