Yeah, Monty Python and the Holy Grail is by far and away the winner. Ever gone to a party where half the chatter was Monty Python quotes? I thought the Monty Python was funny because it was unexpected and surreal.
In a distant second is The Hitchhiker's Guide to the Galaxy. Even worse, it's usually quoted by people who straight up don't get it. ;__;
Seriously, one person began talking about something being as unlikely as a giant vat of custard upending itself (obvious Hitchhiker reference), and I asked him if he'd fly in a ship powered by the improbability drive, and he says "I actually never figured out how the improbability drive factored into it."
HNNNNNNNNNNNNNNNG