i recognise this. i do pen and paper still but i do also write bugs. when i do i try to make test programs to learn why, and ideally recognise where my pen and paper whent wrong, because those are gaps in my real understanding of how my language, the program or interactions with its environment and platform really work. Needless to say i always find myself having lots to learn still :). i think in reality only once or twice i wrote a program truly free of bugs. relatively trivial programs ofc (simple socket client/server with basic binary protocol or so. easy to reason about, no complex sync or threading requirements).

i never use syntax highlighting. one day someone told me it was very distracting, i turned it off and suddenly things were calm. Maybe its just taste but i do find it helpful. you really read stuff rather than assuming some color happening means its correct or incorrect subconsciously