There’s a vending machine in my workplace – a typical one with a keypad that lets you select the snack or beverage you want. There are 3 slots with Pepsi (numbered 53, 54, 55) and I’ve just realized that I always punch 54 in to avoid off-by-one errors… That left me feeling sad for some reason. 
As far as geek reflexes go, this one isn’t that bad