Shoelaces. I doubt if I have spent more than half a dozen inner-city coffee chats in the past 40 years without this topic rising to the cup's surface like an undrunken marshmallow.
Sixties movie siren Mamie Van Doren - could we ever forget The Beat Generation, or, most especially, High School Confidential? - once opined that you can tell the cut of a man's jib from his choice in office chairs.
We live in a phenomenal time. Rational thinkers fight, hiss and scratch out each others' eyes long into the night arguing which phenomena should head the list.