I feel the same! One bit of advice has helped me take better advantage of those small chunks of time- "Park facing downhill." I don't remember where I first heard it, but the idea is to stop somewhere naturally conducive to resuming work. Start making the list, and stop at a point where it's really easy to write down the next few items. Or leave the really easy bit of code for next time.

I'm not good at it, because I prefer to cross things off when I finish them, but when I can pull it off it saves some of that time getting oriented to what I'm working on.