Long before there was an internet, people were playing chess with each other through the mail. Long before a bunch of MIT hackers made two spaceships move around an oscilloscope screen hooked up to a PDP-1 mainframe, we were gathering around kitchen tables to play games with and against each other on boards or bits of paper. Without these antecedents, video games wouldn't exist in any recognisable form.
Playing Quarrel for the first time is one of the strangest gaming experiences I've had for a while, and it was definitely unrelated to the 12th cup of tea of the day. Sometimes games feel so familiar and perfectly formed that you assume that you must have played them before in some nascent form, possibly sometime in the late 1980s before mullets were officially outlawed.