> Who was ever writing on the back of cigarette packs?

British officers planning trench raids in the front lines during WWI. Or, at least, that's where I've been told the expression originates.

Really, though, is it impossible to imagine no one, ever, using a cigarette pack to jot something down? It's a colloquialism. It doesn't even have to be taken literally to make sense. What is gained by questioning it on that level?

this is funny because I know so many people who always note down phone numbers and such for the day on cigarette packs. sometimes even carrying a few with them all the time.

in india.

Smokers who didn't have napkins or envelopes handy, presumably.