Writing with pen and paper on the subway is all sorts of ridiculous. For one, it's outside of the cultural norm of the subway system. You read, you listen to your mp3 or play games with your phone, you flip through magazines. Pen and paper are just pompous things of the past. People look at you funny, and secretly think shit like, "I hope they don't slip up and get pen on me." It's a really pompous environment. Handling a pen is almost as bad as putting a wet umbrella on a seat (OK, not really. That's like a sin of the highest degree).
Let me tell you people who don't ride the subway - it can be an intimidating thing. Other subway people judge you if you look at the subway map or talk to loud or look around a lot. There's this code of quiet, and this code of how much room it's acceptable to take. An open spiral, during a crowded train ride, will violate that code.
But doodling on the iPod is alright. It's on the list of socially acceptable things. So my anxiety is quelled.
It's not just me, man, it's like...scientific fact or something.