I don’t have a problem. My wife thinks it strange that I always have a pen in my pocket - but I feel that she also admires the practicality of it. Almost the first thing I do on getting a new computer is to install software for taking and cross-referencing notes - but everyone does that, don’t they? And when I’m travelling and want to be able to take notes without whipping out a laptop and typing a password, then I use a pocketmod.
What’s a pocketmod? It’s a little A7-size booklet with 8 pages on it that you can stuff in your back pocket and take notes on whenever you need it.
So just a folded piece of A4 then? Yes and no. It is folded up into 8 pieces but then I insert a critical tear into the pattern and fold it up like a book so I can easily flip from one page to another.
The pocketmod website is based around the idea that you preprint the page with things like your calendar for the week, todo lists, etc. and they and others provide software to turn arbitrary documents into pocketmods (for example, Software for OSX). But, for me, it’s just a spare piece of A4 that’s blank on one side - an EasyJet flight itinerary or similar.
(Note: nothing special about A4 paper - works just as well with US letter size.)