[throwaway821909]

So much emphasis on thinking about gear changes does seem a bit unfamiliar to me - but it could just be since my first driving experience was also manual, I was learning all this in the background while my main focus was trying not to hit anything.

Never did anything as exciting as you but I do feel like maybe being a passenger for so many years gives you an ear for when a gear change is needed, and you hear "sorry, wrong gear" and feel the lack of acceleration or whatever. As for /why/, I just imagined cycling up a hill.

[aussiesnack]

Good point on cycling. I think it honed my intuition about gear changes too. I even had a Raleigh Chopper for a while. It sported an actual gear stick centred on the frame. I thought it the coolest thing anyone had ever sat on.