As someone who’s flown since early childhood and racked up well over 1.5 million miles / 2.4 million kilometers in the air, I was amused by your list. Business & First passengers are given socks in their amenity kit; I doubt they are intended to be pulled over one’s shoes. Standing in the aisle and walking around, though these days prohibited on the grounds of security, can make all the difference between having a blood clot form and being healthy at the end of the flight, especially on long-haul trips. As for bringing food on board, unless one wants the overly-salty tiny-portioned junk most airlines serve in Economy, it’s the only option for avoiding hunger — unless you think snacking on those candy bars and potato chips is a good idea (hint: it’s not, at all).
Personally I concluded a long time ago that the entire commercial flying experience in Economy is designed to instill entrepreneurial desire in even the most sedentary individual: it’s so awful that one is motivated to start one’s own company in order to make enough money that one can fly either Business/First or acquire one’s own jet. At which point, one more or less can do whatever one wants.