Originally Posted by HKG_Flyer1
That's strange. On long-haul flights, the substantial majority of pax in the F and J cabins (or at least those who appear to be regular travelers) remove their shoes immediately upon boarding or shortly after departure. Indeed, I've been on some F sleeper suites which appear to have foot lockers designed into them.
That's why you are provided socks in your amenity bag - put them on!