Jeffrey has a surprisingly good grasp of what the world was like between 1980-2010, for a man from 2881, but too far before and after that and he has no idea what the hell was going on. XD
It's this weird situation where he knows "It's Greek to me" means "It's gibberish and way out of my comfort zone," but he has no idea who the Greeks were. And he knows Buck Rogers means "spaceman," but not what that is referencing.
This also results in him knowing snippets of Bad High School Shakespeare, all of 1984 (Because the movie was indeed released in 1984 and too many high schools have had to suffer through it since), and every line in the movie Heathers.