“Photographer nose itcher” is one that comes to mind.

It’s not that the rationale doesn’t make sense (imagine trying to concentrate a camera and suddenly being itchy and wishing you had someone scratch you so you don’t have to unconcentrate your camera so you can free a hand in order to itch the itchy part), but imagine a second person following you around for that purpose in particular, like a photographer’s equivalent to the Piss Boy.