Sleeping in a bed is an arbitrary habit that you've grown comfortable with, why not sleep on the floor, or in the bath? Because contrary to what you say, sleep

Sleeping in a bed is an arbitrary habit that you've grown comfortable with, why not sleep on the floor, or in the bath? Because contrary to what you say, sleeping in a bed is not just an arbitrary habit. The bed is a special purpose piece of furniture, optimised for sleeping in. The use of f-key to step through a program is OTOH simply an accident of history. The f-keys were chosen because they were there. Had they not been, some other solution would have been invented, using the keys that were there, and (this is my point) the solution would have been just as good!